This file was created by the TYPO3 extension publications --- Timezone: CEST Creation date: 2026-04-15 Creation time: 07:35:48 --- Number of references 436 article 2024 11 10.1103/PhysRevResearch.6.043153 Phys. Rev. Res. 6 S. Böhringer A. Friedrich article Janson2024 Quantum-clock interferometry has been suggested as a quantum probe to test the universality of free fall and the universality of gravitational redshift. In typical experimental schemes, it seems advantageous to employ Doppler-free E1–M1 transitions which have so far been investigated in quantum gases at rest. Here, we consider the fully quantized atomic degrees of freedom and study the interplay of the quantum center-of-mass (COM)—that can become delocalized—together with the internal clock transitions. In particular, we derive a model for finite-time E1–M1 transitions with atomic intern–extern coupling and arbitrary position-dependent laser intensities. We further provide generalizations to the ideal expressions for perturbed recoilless clock pulses. Finally, we show, at the example of a Gaussian laser beam, that the proposed quantum-clock interferometers are stable against perturbations from varying optical fields for a sufficiently small quantum delocalization of the atomic COM. 2024 5 10.1116/5.0178230 AVS Quantum Science 6 G. Janson A. Friedrich R. Lopp article 10.1116/5.0185291 This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more kilometer—scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions. 2024 5 10.1116/5.0185291 AVS Quantum Science 6 S. Abend et al. article Asano2024 2024 4 10.1103/PRXQuantum.5.020322 PRX Quantum 5 T. Asano E. Giese F. Di Pumpo article PhysRevResearch.6.013285 2024 3 10.1103/PhysRevResearch.6.013285 Phys. Rev. Res. 6 J. Ströhle R. Lopp article PhysRevResearch.6.013186 2024 2 10.1103/PhysRevResearch.6.013186 Phys. Rev. Res. 6 M. E. N. Tschaffon J. Seiler article di_pumpo_optimal_2024 Several terrestrial detectors for gravitational waves and dark matter based on long-baseline atom interferometry are currently in the final planning stages or already under construction. These upcoming vertical sensors are inherently subject to gravity and thus feature gradiometer or multi-gradiometer configurations using single-photon transitions for large momentum transfer. While there has been significant progress on optimizing these experiments against detrimental noise sources and for deployment at their projected sites, finding optimal configurations that make the best use of the available resources is still an open issue. Even more, the fundamental limit of the device's sensitivity is still missing. Here, we fill this gap and show that (a) resonant-mode detectors based on multi-diamond fountain gradiometers achieve the optimal, shot-noise limited, sensitivity if their height constitutes 20% of the available baseline; (b) this limit is independent of the dark matter oscillation frequency; and (c) doubling the baseline decreases the ultimate measurement uncertainty by approximately 65%. Moreover, we propose a multi-diamond scheme with less mirror pulses where the leading-order gravitational phase contribution is suppressed and compare it to established geometries and demonstrate that both configurations saturate the same fundamental limit. 2024 1 1 10.1116/5.0175683 AVS Quantum Science 6 F. Di Pumpo A. Friedrich E. Giese article bott_atomic_2023 Single-photon transitions are one of the key technologies for designing and operating very-long-baseline atom interferometers tailored for terrestrial gravitational-wave and dark-matter detection. Since such setups aim at the detection of relativistic and beyond-Standard-Model physics, the analysis of interferometric phases as well as of atomic diffraction must be performed to this precision and including these effects. In contrast, most treatments focused on idealized diffraction so far. Here, we study single-photon transitions, both magnetically induced and direct ones, in gravity and Standard-Model extensions modeling dark matter as well as Einstein-equivalence-principle violations. We take into account relativistic effects like the coupling of internal to center-of-mass degrees of freedom, induced by the mass defect, as well as the gravitational redshift of the diffracting light pulse. To this end, we also include chirping of the light pulse required by terrestrial setups, as well as its associated modified momentum transfer for single-photon transitions. 2023 11 10.1116/5.0174258 AVS Quantum Science 5 A. Bott F. Di Pumpo E. Giese inbook Tschaffon2023 We provide an introduction for physicists into the Riemann Hypothesis. For this purpose, we first introduce, and then compare and contrast the Riemann function and the Dirichlet L-functions, with the Titchmarsh counterexample. Whereas the first two classes of functions are expected to satisfy the Riemann Hypothesis, the Titchmarsh counterexample is known to violate it. Throughout our article we employ elementary mathematical techniques known to every physicist. Needless to say, we do not verify the Riemann Hypothesis but suggest heuristic arguments in favor of it. We also build a bridge to quantum mechanics by interpreting the Dirichlet series central to this field as a superposition of probability amplitudes leading us to an unusual potential with a logarithmic energy spectrum opening the possibility of factoring numbers. 2023 9 10.1007/978-3-031-32469-7_7 Sketches of Physics: The Celebration Collection M. E. N. Tschaffon I. Tkáčová H. Maier W. P. Schleich article 2023 6 10.12693/APhysPolA.143.S112 Acta Physica Polonica A 143 F. Gleisberg W. P. Schleich article Friedrich_2023 2023 6 10.12693/APhysPolA.143.S52 Acta Physica Polonica A 143 A. Friedrich D. Moll M. Freyberger L. Plimak W. P. Schleich article tschaffon_average_2023 2023 4 27 10.1103/PhysRevResearch.5.023063 Phys. Rev. Res. 5 Publisher: American Physical Society M. E. N. Tschaffon J. Seiler M. Freyberger article Boegel_2023 Motivated by the recent experimental realization of ultracold quantum gases in shell topology, we propose a straightforward implementation of matter-wave lensing techniques for shell-shaped Bose–Einstein condensates. This approach allows to significantly extend the free evolution time of the condensate shell after release from the trap and enables the study of novel quantum many-body effects on curved geometries. With both analytical and numerical methods we derive optimal parameters for realistic schemes to conserve the shell shape of the condensate for times up to hundreds of milliseconds. 2023 4 27 10.1088/2058-9565/acc969 Quantum Science and Technology 8 P. Boegel A. Wolf M. Meister M. A. Efremov article Glasbrenner_2023 We employ the Markov approximation and the well-known Fresnel-integral to derive in ‘one-line’ the familiar expression for the Landau–Zener transition probability. Moreover, we provide numerical as well as analytical justifications for our approach, and identify three characteristic motions of the probability amplitude in the complex plane. 2023 4 13 10.1088/1361-6455/acc774 Journal of Physics B: Atomic, Molecular and Optical Physics 56 E. P. Glasbrenner W. P. Schleich article di_pumpo_universality—clock-rates_2023 2023 3 10.1103/PhysRevD.107.064007 Phys. Rev. D 107 Publisher: American Physical Society F. Di Pumpo A. Friedrich C. Ufrecht E. Giese article PhysRevA.106.032211 2022 9 10.1103/PhysRevA.106.032211 Phys. Rev. A 106 J. Seiler T. Strohm W. P. Schleich article schach_tunneling_2022 We examine the prospects of utilizing matter-wave Fabry–Pérot interferometers for enhanced inertial sensing applications. Our study explores such tunneling-based sensors for the measurement of accelerations in two configurations: (a) a transmission setup, where the initial wave packet is transmitted through the cavity and (b) an out-tunneling scheme with intra-cavity generated initial states lacking a classical counterpart. We perform numerical simulations of the complete dynamics of the quantum wave packet, investigate the tunneling through a matter-wave cavity formed by realistic optical potentials and determine the impact of interactions between atoms. As a consequence we estimate the prospective sensitivities to inertial forces for both proposed configurations and show their feasibility for serving as inertial sensors. 2022 8 10.1140/epjqt/s40507-022-00140-3 EPJ Quantum Technology 9 P. Schach A. Friedrich J. R. Williams W. P. Schleich E. Giese article schleich_2021 2022 7 https://doi.org/10.11588/diglit.61622.11 Heidelberger Akademie der Wissenschaften: Jahrbuch 2021 W. P. Schleich article PhysRevA.106.013309 2022 7 10.1103/PhysRevA.106.013309 Phys. Rev. A 106 A. Wolf P. Boegel M. Meister A. Balaz N. Gaaloul M. A. Efremov article jenewein_bragg-diffraction-induced_2022 2022 6 10.1103/PhysRevA.105.063316 Phys. Rev. A 105 Publisher: American Physical Society J. Jenewein S. Hartmann A. Roura E. Giese article rozenman_periodic_2022 2022 5 10.1103/PhysRevLett.128.214101 Phys. Rev. Lett. 128 Publisher: American Physical Society G. G. Rozenman W. P. Schleich L. Shemer A. Arie article di_pumpo_light_2022 2022 4 10.1103/PhysRevD.105.084065 Phys. Rev. D 105 Publisher: American Physical Society F. Di Pumpo A. Friedrich A. Geyer C. Ufrecht E. Giese article doi:10.1116/5.0074429 2022 3 10.1116/5.0074429 AVS Quantum Science 4 F. Ullinger M. Zimmermann W. P. Schleich article rodrigues_goncalves_bright_2022 We investigate bright and dark diffractive focusing emerging in the free propagation of specific wave profiles. These general wave phenomena manifest themselves in matter, water, and classical waves. In this article, we lay the foundations for these effects and illustrate their origin in Wigner phase space. Our theoretical studies are supported by experimental demonstrations of dark focusing in water waves. Moreover, by using different phase slits we analyze several aspects of bright and dark focusing for classical and matter waves. 2022 2 10.1007/s00340-022-07755-5 Applied Physics B 128 M. Rodrigues Gonçalves G. G. Rozenman M. Zimmermann M. A. Efremov W. B. Case A. Arie L. Shemer W. P. Schleich article asmann_light-pulse_2022 2022 2 10.1103/PhysRevResearch.4.013115 Phys. Rev. Research 4 Publisher: American Physical Society T. Aßmann F. Di Pumpo E. Giese article https://doi.org/10.18725/oparu-43717 2022 1 10.18725/OPARU-43717 Master Thesis DDC 530 / Physics, Quantum theory, Interferometry, Atom interferometry, Atominterferometrie, Quantenmechanik G. Janson article Happ_2022 We study a heavy–heavy–light three-body system confined to one space dimension in the regime where an excited state in the heavy–light subsystems becomes weakly bound. The associated two-body system is characterized by (i) the structure of the weakly-bound excited heavy–light state and (ii) the presence of deeply-bound heavy–light states. The consequences of these aspects for the behavior of the three-body system are analyzed. We find a strong indication for universal behavior of both three-body binding energies and wave functions for different weakly-bound excited states in the heavy–light subsystems. 2022 1 10.1088/1361-6455/ac3cc8 Journal of Physics B: Atomic, Molecular and Optical Physics 55 L. Happ M. Zimmermann M. A. Efremov article schleich_2021 2021 12 10.1007/978-3-662-63808-8_1 W. P. Schleich article di_pumpo_gravitational_2021 2021 11 11 10.1103/PRXQuantum.2.040333 PRX Quantum 2 Publisher: American Physical Society F. Di Pumpo C. Ufrecht A. Friedrich E. Giese W. P. Schleich W. G. Unruh article Happ_2021 We provide an analytical proof of universality for bound states in one-dimensional systems of two and three particles, valid for short-range interactions with negative or vanishing integral over space. The proof is performed in the limit of weak pair-interactions and covers both binding energies and wave functions. Moreover, in this limit the results are formally shown to converge to the respective ones found in the case of the zero-range contact interaction. 2021 11 10.1088/1361-6455/ac3b3f Journal of Physics B: Atomic, Molecular and Optical Physics 54 L. Happ M. A. Efremov article 2021 We propose a straightforward implementation of the phenomenon of diffractive focusing with uniform atomic Bose–Einstein condensates. Both, analytical as well as numerical methods not only illustrate the influence of the atom–atom interaction on the focusing factor and the focus time, but also allow us to derive the optimal conditions for observing focusing of this type in the case of interacting matter waves. 2021 10 19 10.1088/1361-6455/ac2ab6 J. Phys. B: At. Mol. Opt. Phys. 54 P. Boegel M. Meister J.-N. Siemß N. Gaaloul M. A. Efremov W. P. Schleich article An early approach to include pointers representing measurement devices into quantum mechanics was given by von Neumann. Based on this idea, we model such pointers by qubits and couple them to a free particle, in analogy to a classical time-of-flight arrangement. The corresponding Heisenberg dynamics leads to pointer observables whose expectation values allow us to reconstruct the particle’s momentum distribution via the characteristic function. We investigate different initial qubit states and find that such a reconstruction can be considerably simplified by initially entangled pointers. 2021 10 16 10.1140/epjd/s10053-021-00282-6 The European Physical Journal D 75 B. Konrad F. Di Pumpo M. Freyberger article battelier_exploring_2021 We present the scientific motivation for future space tests of the equivalence principle, and in particular the universality of free fall, at the 10− 17 level or better. Two possible mission scenarios, one based on quantum technologies, the other on electrostatic accelerometers, that could reach that goal are briefly discussed. This publication is a White Paper written in the context of the Voyage 2050 ESA Call for White Papers. 2021 9 10.1007/s10686-021-09718-8 Experimental Astronomy 51 B. Battelier J. Bergé A. Bertoldi L. Blanchet K. Bongs P. Bouyer C. Braxmaier D. Calonico P. Fayet N. Gaaloul C. Guerlin A. Hees P. Jetzer C. Lämmerzahl S. Lecomte C. Le Poncin-Lafitte S. Loriani G. Métris M. Nofrarias E. Rasel S. Reynaud M. Rothacher A. Roura C. Salomon S. Schiller W. P. Schleich C. Schubert C. F. Sopuerta F. Sorrentino T. J. Sumner G. M. Tino P. Tuckey W. von Klitzing L. Wörner P. Wolf M. Zelan article seiler_geometric_2021 2021 9 10.1103/PhysRevA.104.032218 Phys. Rev. A 104 Publisher: American Physical Society J. Seiler T. Strohm W. P. Schleich article kling_high-gain_2021 2021 9 10.1103/PhysRevResearch.3.033232 Phys. Rev. Research 3 Publisher: American Physical Society P. Kling E. Giese C. M. Carmesin R. Sauerbrey W. P. Schleich article weisman_diffractive_2021 2021 7 2 10.1103/PhysRevLett.127.014303 Phys. Rev. Lett. 127 Publisher: American Physical Society D. Weisman C. M. Carmesin G.G. Rozenman M. A. Efremov L. Shemer W. P. Schleich A. Arie article doi:10.1063/5.0048806 2021 4 29 10.1063/5.0048806 The Journal of Chemical Physics 154 K. Soukup F. Di Pumpo T. Aßmann W. P. Schleich E. Giese article Rozenman2021 We study phase contributions of wave functions that occur in the evolution of Gaussian surface gravity water wave packets with nonzero initial momenta propagating in the presence and absence of an effective external linear potential. Our approach takes advantage of the fact that in contrast to matter waves, water waves allow us to measure both their amplitudes and phases. 2021 4 16 10.1140/epjs/s11734-021-00096-y The European Physical Journal Special Topics 230 G. G. Rozenman M. Zimmermann M. A. Efremov W. P. Schleich W. B. Case D. M. Greenberger L. Shemer A. Arie article lachmann_ultracold_2021 Bose-Einstein condensates ({BECs}) in free fall constitute a promising source for space-borne interferometry. Indeed, {BECs} enjoy a slowly expanding wave function, display a large spatial coherence and can be engineered and probed by optical techniques. Here we explore matter-wave fringes of multiple spinor components of a {BEC} released in free fall employing light-pulses to drive Bragg processes and induce phase imprinting on a sounding rocket. The prevailing microgravity played a crucial role in the observation of these interferences which not only reveal the spatial coherence of the condensates but also allow us to measure differential forces. Our work marks the beginning of matter-wave interferometry in space with future applications in fundamental physics, navigation and earth observation. 2021 2 26 10.1038/s41467-021-21628-z Nature Comm. 12 M.D. Lachmann H. Ahlers D. Becker A. N. Dinkelaker J. Grosse O. Hellmig H. Müntinga V. Schkolnik S. T. Seidel T. Wendrich A. Wenzlawski B. Carrick N. Gaaloul D. Lüdtke C. Braxmaier W. Ertmer M. Krutzik C. Lämmerzahl A. Peters W. P. Schleich K. Sengstock A. Wicht P. Windpassinger E. M. Rasel article PhysRevA.103.023305 2021 2 3 10.1103/PhysRevA.103.023305 Phys. Rev. A 103 C. Ufrecht article frye_bose-einstein_2021 Microgravity eases several constraints limiting experiments with ultracold and condensed atoms on ground. It enables extended times of flight without suspension and eliminates the gravitational sag for trapped atoms. These advantages motivated numerous initiatives to adapt and operate experimental setups on microgravity platforms. We describe the design of the payload, motivations for design choices, and capabilities of the Bose-Einstein Condensate and Cold Atom Laboratory ({BECCAL}), a {NASA}-{DLR} collaboration. {BECCAL} builds on the heritage of previous devices operated in microgravity, features rubidium and potassium, multiple options for magnetic and optical trapping, different methods for coherent manipulation, and will offer new perspectives for experiments on quantum optics, atom optics, and atom interferometry in the unique microgravity environment on board the International Space Station. 2021 1 4 10.1140/epjqt/s40507-020-00090-8 The European Physical Journal Quantum Technology 8 K. Frye S. Abend W. Bartosch A. Bawamia D. Becker H. Blume C. Braxmaier S.-W. Chiow M. A. Efremov W. Ertmer P. Fierlinger T. Franz N. Gaaloul J. Grosse C. Grzeschik O. Hellmig V. A. Henderson W. Herr U. Israelsson J. Kohel M. Krutzik C. Kürbis C. Lämmerzahl M. List D. Lüdtke N. Lundblad J. P. Marburger M. Meister M. Mihm H. Müller H. Müntinga A. M. Nepal T. Oberschulte A. Papakonstantinou J. Perovs̆ek A. Peters A. Prat E. M. Rasel A. Roura M. Sbroscia W. P. Schleich C. Schubert S. T. Seidel J. Sommer C. Spindeldreier D. Stamper-Kurn B. K. Stuhl M. Warner T. Wendrich A. Wenzlawski A. Wicht P. Windpassinger N. Yu L. Wörner article PhysRevA.102.063326 2020 12 22 10.1103/PhysRevA.102.063326 Phys. Rev. A 102 S. Hartmann J. Jenewein S. Abend A. Roura E. Giese article PhysRevResearch.2.043240 2020 11 16 10.1103/PhysRevResearch.2.043240 Phys. Rev. Research 2 C. Ufrecht F. Di Pumpo A. Friedrich A. Roura C. Schubert Dennis Schlippert E. M. Rasel W. P. Schleich E. Giese article Seiler_2020 We analyze the information an attacker can obtain on the numbers generated by a user by measurements on a subsystem of a system consisting of two entangled two-level systems. The attacker and the user make measurements on their respective subsystems, only. Already the knowledge of the density matrix of the subsystem of the user completely determines the upper bound on the information accessible to the attacker. We compare and contrast this information to the appropriate bounds provided by quantum state discrimination. 2020 9 21 10.1088/1367-2630/abac73 New J. Phys. 22 J. Seiler T. Strohm W. P. Schleich article PhysRevA.102.027302 2020 8 20 10.1103/PhysRevA.102.027302 Phys. Rev. A 102 C. Ufrecht E. Giese article PhysRevA.101.053615 2020 5 8 10.1103/PhysRevA.101.053615 Phys. Rev. A 101 C. Ufrecht E. Giese article PhysRevA.101.053610 2020 5 8 10.1103/PhysRevA.101.053610 Phys. Rev. A 101 J. Jenewein E. Giese S. Abend A. Roura E.M. Rasel W.P. Schleich article PhysRevResearch.2.023027 2020 4 10 10.1103/PhysRevResearch.2.023027 Phys. Rev. Research 2 C. M. Carmesin P. Kling E. Giese R. Sauerbrey W. P. Schleich article spec_mirror 2020 4 4 https://doi.org/10.1016/bs.po.2019.11.006 A Tribute to Emil Wolf Progress in Optics 65 F. Di Pumpo A. Friedrich E. Giese A. Roura H. Lemmel D.M. Greenberger E.M. Rasel W.P. Schleich article Mukamel_2020 Conventional spectroscopy uses classical light to detect matter properties through the variation of its response with frequencies or time delays. Quantum light opens up new avenues for spectroscopy by utilizing parameters of the quantum state of light as novel control knobs and through the variation of photon statistics by coupling to matter. This Roadmap article focuses on using quantum light as a powerful sensing and spectroscopic tool to reveal novel information about complex molecules that is not accessible by classical light. It aims at bridging the quantum optics and spectroscopy communities which normally have opposite goals: manipulating complex light states with simple matter e.g. qubits versus studying complex molecules with simple classical light, respectively. Articles cover advances in the generation and manipulation of state-of-the-art quantum light sources along with applications to sensing, spectroscopy, imaging and interferometry. 2020 3 16 10.1088/1361-6455/ab69a8 J. Phys. B: At. Mol. Opt. Phys. 53 S. Mukamel M. Freyberger W. P. Schleich M. Bellini R. W. Boyd L. L. Sánchez-Soto M. Barbieri A. Paterova L. Krivitsky K. Dorfman F. Schlawin V. Sandoghdar M. Raymer A. Marcus T. Goodson S. Asban M. Scully G. Agarwal T. Peng F. Laussy article DiPumpo2019 We revisit the pointer-based measurement concept of von Neumann which allows us to model a quantum counterpart of the classical time-of-flight (ToF) momentum. Our approach is based on the Hamiltonian for a particle interacting with two quantum pointers serving as basic measurement devices. The corresponding dynamics leads to a pointer-based ToF observable for the operational momentum of the particle. We can consider single measurements of our quantum pointers and show that this process will result in a state reduction for a single particle being downstream of the time-of-flight setup. 2019 8 06 1434-6079 10.1140/epjd/e2019-100226-1 The European Physical Journal D 73 163 8 https://doi.org/10.1140/epjd/e2019-100226-1 F. Di Pumpo M. Freyberger article PhysRevLett.123.083601 2019 8 10.1103/PhysRevLett.123.083601 Phys. Rev. Lett. 123 American Physical Society 083601 https://link.aps.org/doi/10.1103/PhysRevLett.123.083601 O. Amit Y. Margalit O. Dobkowski Y. Japha M. Zimmermann M. A. Efremov F. A. Narducci E. M. Rasel W. P. Schleich R. Folman article Zimmermann_2019 2019 7 10.1088/1367-2630/ab2e8c New Journal of Physics 21 {IOP} Publishing 073031 7 https://doi.org/10.1088%2F1367-2630%2Fab2e8c M. Zimmermann M. A. Efremov W. Zeller W. P. Schleich J. P. Davis F. A. Narducci article PhysRevA.100.012709 2019 7 10.1103/PhysRevA.100.012709 Phys. Rev. A 100 American Physical Society 012709 https://link.aps.org/doi/10.1103/PhysRevA.100.012709 L. Happ M. Zimmermann S. I. Betelu W. P. Schleich M. A. Efremov article Menzel:19 We investigate the role of the spatial mode function in a single-photon experiment designed to demonstrate the principle of complementarity. Our approach employs entangled photons created by spontaneous parametric downconversion from a pump mode in a TEM01 mode together with a double slit. Measuring the interference of the signal photons behind the double slit in coincidence with the entangled idler photons at different positions, we select signal photons of different mode functions. When the signal photons belong to the TEM01-like double-hump mode, we obtain almost perfect visibility of the interference fringes, and no ``which slit'' information is available in the idler photon detected before the slits. This result is remarkable because the entangled signal and idler photon pairs are created each time in only one of the two intensity humps. However, when we break the symmetry between the two maxima of the signal photon mode structure, the paths through the slits for these additional photons become distinguishable and the visibility vanishes. It is the mode function of the photons selected by the detection system that decides if interference or ``which slit'' information is accessible in the experiment. 2019 6 10.1364/JOSAB.36.001668 J. Opt. Soc. Am. B 36 OSA 1668--1675 6 Electric fields; Numerical simulation; Phase matching; Phase shift; Photonic entanglement; Photons http://josab.osa.org/abstract.cfm?URI=josab-36-6-1668 R. Menzel R. Marx D. Puhlmann A. Heuer W. P. Schleich article PhysRevA.99.053823 2019 5 10.1103/PhysRevA.99.053823 Phys. Rev. A 99 American Physical Society 053823 https://link.aps.org/doi/10.1103/PhysRevA.99.053823 P. Kling E. Giese C. M. Carmesin R. Sauerbrey W. P. Schleich article PhysRevLett.122.124302 2019 3 10.1103/PhysRevLett.122.124302 Phys. Rev. Lett. 122 American Physical Society 124302 https://link.aps.org/doi/10.1103/PhysRevLett.122.124302 G. G. Rozenman M. Zimmermann M. A. Efremov W. P. Schleich L. Shemer A. Arie inproceedings 2019 10.3254/978-1-61499-937-9-345 Foundations of quantum theory 197 IOS Press

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Proceedings of the International School of Physics "Enrico Fermi" E. M. Rasel, W. P. Schleich and S. Wölk 345-392 S. Abend M. Gersemann C. Schubert D. Schlippert E. M. Rasel M. Zimmermann M. A. Efremov A. Roura F. A. Narducci W. P. Schleich article Lorianieaax8966 The phase of matter waves depends on proper time and is therefore susceptible to special-relativistic (kinematic) and gravitational (redshift) time dilation. Hence, it is conceivable that atom interferometers measure general-relativistic time-dilation effects. In contrast to this intuition, we show that (i) closed light-pulse interferometers without clock transitions during the pulse sequence are not sensitive to gravitational time dilation in a linear potential. (ii) They can constitute a quantum version of the special-relativistic twin paradox. (iii) Our proposed experimental geometry for a quantum-clock interferometer isolates this effect. 2019 10.1126/sciadv.aax8966 Science Advances 5 American Association for the Advancement of Science eaax8966 10 S. Loriani A. Friedrich C. Ufrecht F. Di Pumpo S. Kleinert S. Abend N. Gaaloul C. Meiners C. Schubert D. Tell É. Wodey M. Zych W. Ertmer A. Roura D. Schlippert W. P. Schleich E. M. Rasel E. Giese inbook 2019 Jahrbuch 2018 Heidelberger Akademie der Wissenschaften 212-215 W. P. Schleich inproceedings 2019 Foundations of quantum theory 197 IOS Press

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Proceedings of the International School of Physics "Enrico Fermi" E. M. Rasel, W. P. Schleich and S. Wölk XV-XVIII E. M. Rasel W. P. Schleich S. Wölk article PhysRevA.99.013627 2019 1 10.1103/PhysRevA.99.013627 Phys. Rev. A 99 American Physical Society 013627 https://link.aps.org/doi/10.1103/PhysRevA.99.013627 E. Giese A. Friedrich F. Di Pumpo A. Roura W. P. Schleich D. M. Greenberger E. M. Rasel article The proposed mission “Space Atomic Gravity Explorer” (SAGE) has the scientific objective to investigate gravitational waves, dark matter, and other fundamental aspects of gravity as well as the connection between gravitational physics and quantum physics using new quantum sensors, namely, optical atomic clocks and atom interferometers based on ultracold strontium atoms. 2019 1434-6079 The European Physical Journal D 73 228 11 https://doi.org/10.1140/epjd/e2019-100324-6 G. M. Tino Angelo Bassi Giuseppe Bianco K. Bongs P. Bouyer Luigi Cacciapuoti Salvatore Capozziello Xuzong Chen Maria L. Chiofalo Andrei Derevianko W. Ertmer N. Gaaloul Patrick Gill Peter W. Graham Jason M. Hogan Luciano Iess Mark A. Kasevich Hidetoshi Katori Carsten Klempt Xuanhui Lu Long-Sheng Ma H. Müller Nathan R. Newbury Chris W. Oates A. Peters Nicola Poli E. M. Rasel Gabriele Rosi A. Roura C. Salomon S. Schiller W. P. Schleich Dennis Schlippert Florian Schreck C. Schubert F. Sorrentino Uwe Sterr Jan W. Thomsen Giuseppe Vallone Flavio Vetrano Paolo Villoresi Wolf Klitzing David Wilkowski P. Wolf Jun Ye N. Yu Mingsheng Zhan article Since the first proof-of-principle experiments over 25 years ago, atom interferometry has matured to a versatile tool that can be used in fundamental research in particle physics, general relativity and cosmology. At the same time, atom interferometers are currently moving out of the laboratory to be used as ultraprecise quantum sensors in metrology, geophysics, space, civil engineering, oil and minerals exploration, and navigation. This Perspective discusses the associated scientific and technological challenges and highlights recent advances. 2019 2522-5820 Nature Reviews Physics 1 731--739 12 https://doi.org/10.1038/s42254-019-0117-4 K. Bongs Michael Holynski Jamie Vovrosh P. Bouyer Gabriel Condon E. Rasel C. Schubert W. P. Schleich A. Roura inproceedings 2019 10.3254/978-1-61499-937-9-47 Foundations of quantum theory 197 IOS Press

Amsterdam, Oxford, Tokyo, Washington DC

Proceedings of the International School of Physics "Enrico Fermi" E. M. Rasel, W. P. Schleich and S. Wölk 47-79 M. O. Scully D. M. Greenberger D. H. Kobe W. P. Schleich article Meister_2019 Atom laser experiments with Bose–Einstein condensates (BECs) performed in ground-based laboratories feature a coherent and directed beam of atoms which is accelerated by gravity. In microgravity the situation is fundamentally different because the dynamics is entirely determined by the repulsive interaction between the atoms and not by the gravitational force. As a result, the output of a space atom laser is a spherical wave slowly expanding away from the initial BEC. We present a thorough theoretical study of this new source of matter waves based on rf outcoupling which exhibits an isotropic distribution both in position and momentum even for an initially anisotropic trap. The unique geometry of such a freely expanding, shell-shaped BEC offers new possibilities for matter waves in microgravity and is complementary to other matter-wave sources prepared by delta-kick collimation or adiabatic expansion. Our work paves the way for the upcoming experimental realization of a space atom laser making use of NASA’s Cold Atom Laboratory on the International Space Station. 2019 1 10.1088/1367-2630/aaf7b5 New Journal of Physics 21 {IOP} Publishing 013039 1 https://doi.org/10.1088%2F1367-2630%2Faaf7b5 M. Meister A. Roura E. M. Rasel W. P. Schleich inproceedings 2019 10.3254/978-1-61499-937-9-119 Foundations of quantum theory 197 IOS Press

Amsterdam, Oxford, Tokyo, Washington DC

Proceedings of the International School of Physics "Enrico Fermi" E. M. Rasel, W. P. Schleich and S. Wölk 119-132 M. O. Scully D. M. Greenberger W. P. Schleich article Schleich_2018 We prove the equivalence of three formulations of the Riemann hypothesis for functions f defined by the four assumptions: (a 1) f satisfies the functional equation f(1 − s) = f(s) for the complex argument s ≡ σ + iτ, (a2) f is free of any pole, (a3) for large positive values of σ the phase θ of f increases in a monotonic way without a bound as τ increases, and (a4) the zeros of f as well as of the first derivative f ′ of f are simple zeros. The three equivalent formulations are: (R1) All zeros of f are located on the critical line σ = 1/2, (R2) All lines of constant phase of f corresponding to merge with the critical line, and (R3) All points where f ′ vanishes are located on the critical line, and the phases of f at two consecutive zeros of f ′ differ by π. Our proof relies on the topology of the lines of constant phase of f dictated by complex analysis and the assumptions (a1)–(a4). Moreover, we show that (R2) implies (R1) even in the absence of (a4). In this case (a4) is a consequence of (R2). 2018 5 10.1088/1402-4896/aabca9 Physica Scripta 93 {IOP} Publishing 065201 6 https://doi.org/10.1088%2F1402-4896%2Faabca9 W. P. Schleich I. Bezděková M. B. Kim P. C. Abbott H. Maier H. L. Montgomery J. W. Neuberger article Happ_2018 We show that the expectation value of the operator defined by the position and momentum operators and with a positive parameter c can serve as a tool to identify quantum non-Gaussian states, that is states that cannot be represented as a mixture of Gaussian states. Our condition can be readily tested employing a highly efficient homodyne detection which unlike quantum-state tomography requires the measurements of only two orthogonal quadratures. We demonstrate that our method is even able to detect quantum non-Gaussian states with positive–definite Wigner functions. This situation cannot be addressed in terms of the negativity of the phase-space distribution. Moreover, we demonstrate that our condition can characterize quantum non-Gaussianity for the class of superposition states consisting of a vacuum and integer multiples of four photons under more than 50 % signal attenuation. 2018 2 10.1088/1367-2630/aaac25 New Journal of Physics 20 {IOP} Publishing 023046 2 https://doi.org/10.1088%2F1367-2630%2Faaac25 L. Happ M. A. Efremov H. Nha W. P. Schleich article doi:10.1080/09500340.2018.1511860 2018 10.1080/09500340.2018.1511860 Journal of Modern Optics Taylor & Francis 1-8 R. Nessler H. Eleuch W. P. Schleich M. O. Scully article doi:10.1080/09500340.2018.1454525 2018 10.1080/09500340.2018.1454525 Journal of Modern Optics 65 Taylor & Francis 1261-1308 11 G. Agarwal R. E. Allen I. Bezděková R. W. Boyd R. Hanson D. L. Hawthorne P. Hemmer M. B. Kim O. Kocharovskaya D. M. Lee S. K. Lidström S. Lidström H. Losert H. Maier J. W. Neuberger M. J. Padgett M. Raizen S. Rajendran E. Rasel W. P. Schleich M. O. Scully G. Shchedrin G. Shvets A. V. Sokolov A. Svidzinsky R. L. Walsworth R. Weiss F. Wilczek A. E. Willner E. Yablonovitch N. Zheludev article Gleisberg_2018 We propose an iterative scheme to factor numbers based on the quantum dynamics of an ensemble of interacting bosonic atoms stored in a trap where the single-particle energy spectrum depends logarithmically on the quantum number. When excited by a time-dependent interaction these atoms perform Rabi oscillations between the ground state and an energy state characteristic of the factors. The number to be factored is encoded into the frequency of the sinusoidally modulated interaction. We show that a measurement of the energy of the atoms at a time chosen at random yields the factors with probability one half. We conclude by discussing a protocol to obtain the desired prime factors employing a logarithmic energy spectrum which consists of prime numbers only. 2018 1 10.1088/1361-6455/aa9957 Journal of Physics B: Atomic, Molecular and Optical Physics 51 {IOP} Publishing 035009 3 https://doi.org/10.1088%2F1361-6455%2Faa9957 F. Gleisberg F. Di Pumpo G. Wolff W. P. Schleich article Scully8131 Using a combination of quantum optics and general relativity, we show that the radiation emitted by atoms falling into a black hole looks like, but is different from, Hawking radiation. This analysis also provides insight into the Einstein principle of equivalence between acceleration and gravity.We show that atoms falling into a black hole (BH) emit acceleration radiation which, under appropriate initial conditions, looks to a distant observer much like (but is different from) Hawking BH radiation. In particular, we find the entropy of the acceleration radiation via a simple laser-like analysis. We call this entropy horizon brightened acceleration radiation (HBAR) entropy to distinguish it from the BH entropy of Bekenstein and Hawking. This analysis also provides insight into the Einstein principle of equivalence between acceleration and gravity. 2018 0027-8424 10.1073/pnas.1807703115 Proceedings of the National Academy of Sciences 115 National Academy of Sciences 8131--8136 32 M. O. Scully S. Fulling D. M. Lee D. N. Page W. P. Schleich A. A. Svidzinsky article Becker2018 Owing to the low-gravity conditions in space, space-borne laboratories enable experiments with extended free-fall times. Because Bose-Einstein condensates have an extremely low expansion energy, space-borne atom interferometers based on Bose-Einstein condensation have the potential to have much greater sensitivity to inertial forces than do similar ground-based interferometers. On 23 January 2017, as part of the sounding-rocket mission MAIUS-1, we created Bose-Einstein condensates in space and conducted 110 experiments central to matter-wave interferometry, including laser cooling and trapping of atoms in the presence of the large accelerations experienced during launch. Here we report on experiments conducted during the six minutes of in-space flight in which we studied the phase transition from a thermal ensemble to a Bose-Einstein condensate and the collective dynamics of the resulting condensate. Our results provide insights into conducting cold-atom experiments in space, such as precision interferometry, and pave the way to miniaturizing cold-atom and photon-based quantum information concepts for satellite-based implementation. In addition, space-borne Bose-Einstein condensation opens up the possibility of quantum gas experiments in low-gravity conditions1,2. 2018 1476-4687 10.1038/s41586-018-0605-1 Nature 562 391-395 7727 https://doi.org/10.1038/s41586-018-0605-1 D. Becker M. D. Lachmann S. T. Seidel H. Ahlers A. N. Dinkelaker J. Grosse O. Hellmig H. Müntinga V. Schkolnik T. Wendrich A. Wenzlawski B. Weps R. Corgier T. Franz N. Gaaloul W. Herr D. Lüdtke S. Amri H. Duncker M. Erbe A. Kohfeldt A. Kubelka-Lange C. Braxmaier E. Charron W. Ertmer M. Krutzik C. Lämmerzahl W. P. Schleich K. Sengstock R. Walser A. Wicht P. Windpassinger E. M. Rasel article Ufrecht_2017 We present analytical studies of a trapped boson-fermion mixture at zero temperature with spin-polarized fermions. Using the Thomas–Fermi approximation for bosons and the local-density approximation for fermions, we find a large variety of different density shapes. In the case of continuous density, we obtain analytic conditions for each configuration for attractive as well as repulsive boson-fermion interaction. Furthermore, we analytically show that all the scenarios we describe are minima of the grand-canonical energy functional. Finally, we provide a full classification of all possible ground states in the interpenetrative regime. Our results also apply to binary mixtures of bosons. 2017 8 10.1088/1367-2630/aa7814 New Journal of Physics 19 {IOP} Publishing 085001 8 https://doi.org/10.1088%2F1367-2630%2Faa7814 C. Ufrecht M. Meister A. Roura W. P. Schleich article Kim_2017 Hauser and Nedić (2005 SIAM J. Optim. 15 915) have pointed out an intriguing property of a perturbed flow line generated by the continuous Newton method: it returns to the unperturbed one once the perturbation ceases to exist. We show that this feature is a direct consequence of the phase being constant along any Newton trajectory, that is, once a phase always that phase. 2017 7 10.1088/1402-4896/aa7ae3 Physica Scripta 92 {IOP} Publishing 085201 8 https://doi.org/10.1088%2F1402-4896%2Faa7ae3 M. B. Kim J. W. Neuberger W. P. Schleich article PhysRevA.96.013827 2017 7 10.1103/PhysRevA.96.013827 Phys. Rev. A 96 American Physical Society 013827 https://link.aps.org/doi/10.1103/PhysRevA.96.013827 L. Zhang G. S. Agarwal W. P. Schleich M. O. Scully article PhysRevLett.118.154301 2017 4 10.1103/PhysRevLett.118.154301 Phys. Rev. Lett. 118 American Physical Society 154301 https://link.aps.org/doi/10.1103/PhysRevLett.118.154301 D. Weisman S. Fu L. Shemer W. P. Schleich A. Arie article Goncalves2017 We illustrate the phenomenon of the focusing of a freely propagating rectangular wave packet using three different tools: (1) the time-dependent wave function in position space, (2) the Wigner phase-space approach, and (3) an experiment using laser light. 2017 3 30 1432-0649 10.1007/s00340-017-6675-1 Applied Physics B 123 121 4 https://doi.org/10.1007/s00340-017-6675-1 M. R. Gonçalves W. B. Case A. Arie W. P. Schleich article Zimmermann2017 The quantum mechanical propagator of a massive particle in a linear gravitational potential derived already in 1927 by Kennard [2, 3] contains a phase that scales with the third power of the time T during which the particle experiences the corresponding force. Since in conventional atom interferometers the internal atomic states are all exposed to the same acceleration a, this {\$}{\$}T^3{\$}{\$}T3-phase cancels out and the interferometer phase scales as {\$}{\$}T^2{\$}{\$}T2. In contrast, by applying an external magnetic field we prepare two different accelerations {\$}{\$}a{\_}1{\$}{\$}a1and {\$}{\$}a{\_}2{\$}{\$}a2for two internal states of the atom, which translate themselves into two different cubic phases and the resulting interferometer phase scales as {\$}{\$}T^3{\$}{\$}T3. We present the theoretical background for, and summarize our progress towards experimentally realizing such a novel atom interferometer. 2017 3 20 1432-0649 10.1007/s00340-017-6655-5 Applied Physics B 123 102 4 https://doi.org/10.1007/s00340-017-6655-5 M. Zimmermann M. A. Efremov A. Roura W. P. Schleich S. A. DeSavage J. P. Davis A. Srinivasan F. A. Narducci S. A. Werner E. M. Rasel incollection MEISTER2017375 Quantum sensors based on matter-wave interferometry are promising candidates for high-precision gravimetry and inertial sensing in space. The favorable sources for the coherent matter waves in these devices are Bose–Einstein condensates. A reliable prediction of their dynamics, which is governed by the Gross–Pitaevskii equation, requires suitable analytical and numerical methods, which take into account the center-of-mass motion of the condensate, its rotation, and its spatial expansion by many orders of magnitude. In this chapter, we present an efficient way to study their dynamics in time-dependent rotating traps that meet this objective. Both an approximate analytical solution for condensates in the Thomas–Fermi regime and dedicated numerical simulations on a variable adapted grid are discussed. We contrast and relate our approach to previous alternative methods and provide further results, such as analytical expressions for the one- and two-dimensional spatial density distributions and the momentum distribution in the long-time limit that are of immediate interest to experimentalists working in this field of research. 2017 1049-250X https://doi.org/10.1016/bs.aamop.2017.03.006 66 Academic Press Advances In Atomic, Molecular, and Optical Physics Ennio Arimondo and Chun C. Lin and Susanne F. Yelin 375 - 438 Bose–Einstein condensate, Gross–Pitaevskii equation, Thomas–Fermi approximation, Scaling approach, Time-dependent rotating trap, Numerical simulation, Hamiltonian formalism, Integrated density distribution http://www.sciencedirect.com/science/article/pii/S1049250X17300174 M. Meister St. Arnold D. Moll M. Eckart E. Kajari M. A. Efremov R. Walser W. P. Schleich article doi:10.1002/prop.201700015 The phenomenon of quantum jumps observed in a single ion stored in a trap brings to light intimate connections between three different concepts of quantum physics: (i) quantum state trajectories, (ii) Gamow states, and (iii) the arrow of time. In particular, it allows us to identify the starting time of the semigroup time evolution. 2017 10.1002/prop.201700015 Fortschritte der Physik 65 1700015 6-8 https://onlinelibrary.wiley.com/doi/abs/10.1002/prop.201700015 A. Bohm P. W. Bryant H. Uncu S. Wickramasekara W. P. Schleich article doi:10.1002/prop.201600092 Quantum phase-space distributions offer a royal road into the fascinating quantum–classical interface; the Wigner function being the first and best example. However, the subject is frequent with subtleties and textbook-level misinformation; e.g. “The Wigner distribution can give wrong answers for some operator expectation values” . Since the Wigner distribution is just another representation of the density matrix, it must yield correct answers. To that end, Marlan Scully has asked at several international conferences (the 2015 Prague conference being one of them) the following question: “Starting with the density matrix (not the Moyal characteristic function), could you give me a simple direct derivation of the Wigner distribution?” Section contains his answer. In Appendix D, we give a related treatment and make contact with other approaches. We hope that as a result of our studies, the Wigner distribution will become more deeply appreciated. 2017 10.1002/prop.201600092 Fortschritte der Physik 65 1600092 6-8 Phase space quantum mechanics, Wigner Weyl distribution, Wigner Weyl symmetric ordering, Weyl and its inverse transform, operator symbol correspondence https://onlinelibrary.wiley.com/doi/abs/10.1002/prop.201600092 J. S. Ben-Benjamin M. B. Kim W. P. Schleich W. B. Case L. Cohen article 2017 Physik Journal 16 8-9 W. P. Schleich article Kling2016 In the quantum regime of the free-electron laser, the dynamics of the electrons is not governed by continuous trajectories but by discrete jumps in momentum. In this article, we rederive the two crucial conditions to enter this quantum regime: (1) a large quantum mechanical recoil of the electron caused by the scattering with the laser and the wiggler field and (2) a small energy spread of the electron beam. In contrast to our recent approach based on nonrelativistic quantum mechanics in a co-moving frame of reference, we now pursue a model in the laboratory frame employing relativistic quantum electrodynamics. 2016 12 15 1432-0649 10.1007/s00340-016-6571-0 Applied Physics B 123 9 1 https://doi.org/10.1007/s00340-016-6571-0 P. Kling R. Sauerbrey P. Preiss E. Giese R. Endrich W. P. Schleich article PhysRevA.94.063619 2016 12 10.1103/PhysRevA.94.063619 Phys. Rev. A 94 American Physical Society 063619 https://link.aps.org/doi/10.1103/PhysRevA.94.063619 E. Giese A. Friedrich S. Abend E. M. Rasel W. P. Schleich article PhysRevLett.117.203003 2016 11 10.1103/PhysRevLett.117.203003 Phys. Rev. Lett. 117 American Physical Society 203003 https://link.aps.org/doi/10.1103/PhysRevLett.117.203003 S. Abend M. Gebbe M. Gersemann H. Ahlers H. Müntinga E. Giese N. Gaaloul C. Schubert C. Lämmerzahl W. Ertmer W. P. Schleich E. M. Rasel article PhysRevLett.116.173601 2016 4 10.1103/PhysRevLett.116.173601 Phys. Rev. Lett. 116 American Physical Society 173601 https://link.aps.org/doi/10.1103/PhysRevLett.116.173601 H. Ahlers H. Müntinga A. Wenzlawski M. Krutzik G. Tackmann S. Abend N. Gaaloul E. Giese A. Roura R. Kuhl C. Lämmerzahl P. Windpassinger K. Sengstock W. P. Schleich W. Ertmer E. M. Rasel article Kaltenbaek2016 Do the laws of quantum physics still hold for macroscopic objects?- this is at the heart of Schrödinger's cat paradox?- or do gravitation or yet unknown effects set a limit for massive particles? What is the fundamental relation between quantum physics and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times and the quality of vacuum and microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) may overcome these limitations and allow addressing such fundamental questions. MAQRO harnesses recent developments in quantum optomechanics, high-mass matter-wave interferometry as well as state-of-the-art space technology to push macroscopic quantum experiments towards their ultimate performance limits and to open new horizons for applying quantum technology in space. The main scientific goal is to probe the vastly unexplored 'quantum-classical' transition for increasingly massive objects, testing the predictions of quantum theory for objects in a size and mass regime unachievable in ground-based experiments. The hardware will largely be based on available space technology. Here, we present the MAQRO proposal submitted in response to the 4th Cosmic Vision call for a medium-sized mission (M4) in 2014 of the European Space Agency (ESA) with a possible launch in 2025, and we review the progress with respect to the original MAQRO proposal for the 3rd Cosmic Vision call for a medium-sized mission (M3) in 2010. In particular, the updated proposal overcomes several critical issues of the original proposal by relying on established experimental techniques from high-mass matter-wave interferometry and by introducing novel ideas for particle loading and manipulation. Moreover, the mission design was improved to better fulfill the stringent environmental requirements for macroscopic quantum experiments. 2016 2196-0763 10.1140/epjqt/s40507-016-0043-7 EPJ Quantum Technology 3 5 1 https://doi.org/10.1140/epjqt/s40507-016-0043-7 R. Kaltenbaek M. Aspelmeyer P. F. Barker A. Bassi J. Bateman K. Bongs S. Bose C. Braxmaier C. Brukner B. Christophe M. Chwalla P.-F. Cohadon A. M. Cruise C. Curceanu K. Dholakia L. Diósi K. Döringshoff W. Ertmer J. Gieseler N. Gürlebeck G. Hechenblaikner A. Heidmann S. Herrmann S. Hossenfelder U. Johann N. Kiesel M. Kim C. Lämmerzahl A. Lambrecht M. Mazilu G. J. Milburn H. Müller L. Novotny M. Paternostro I. Pikovski A. Pilan Zanoni E. M. Rasel S. Reynaud C. J. Riedel M. Rodrigues L. Rondin A. Roura W. P. Schleich J. Schmiedmayer T. Schuldt K. C. Schwab M. Tajmar G. M. Tino H. Ulbricht R. Ursin V. Vedral inbook Schleich2016 The wave-particle dualism, that is the wave nature of particles and the particle nature of light together with the uncertainty relation of Werner Heisenberg and the principle of complementarity formulated by Niels Bohr represent pillars of quantum theory. We provide an introduction into these fascinating yet strange aspects of the microscopic world and summarize key experiments confirming these concepts so alien to our daily life. 2016 978-3-319-31903-2 10.1007/978-3-319-31903-2_19 Springer International Publishing

Cham

M. D. Al-Amri, M. El-Gomati and M. S. Zubairy 483--504 https://doi.org/10.1007/978-3-319-31903-2_19 W. P. Schleich article Kling_2015 The quantum regime of the free-electron laser (FEL) emerges when the discreteness of the momentum of the electron plays a dominant role in the interaction with the laser and the wiggler field. Motivated by a heuristic phase space approach we pursue two different routes to define the transition from the classical FEL to the quantum domain: (i) standard perturbation theory and (ii) the method of averaging. Moreover, we discuss the experimental requirements for realizing a Quantum FEL and connect them to today's capabilities. 2015 12 10.1088/1367-2630/17/12/123019 New Journal of Physics 17 {IOP} Publishing 123019 12 https://doi.org/10.1088%2F1367-2630%2F17%2F12%2F123019 P. Kling E. Giese R. Endrich P. Preiss R. Sauerbrey W. P. Schleich article Neuberger_2015 We analyze the Newton flow of the Riemann zeta function ζ and rederive in an elementary way the Riemann–von Mangoldt estimate of the number of non-trivial zeros below a given imaginary part. The representation of the flow on the Riemann sphere highlights the importance of the North pole as the starting and turning point of the separatrices, that is of the continental divides of the Newton flow. We argue that the resulting patterns may lead to deeper insight into the Riemann hypothesis. For this purpose we also compare and contrast the Newton flow of ζ with that of a function which in many ways is similar to ζ, but violates the Riemann hypothesis. 2015 10 10.1088/0031-8949/90/10/108015 Physica Scripta 90 {IOP} Publishing 108015 10 https://doi.org/10.1088%2F0031-8949%2F90%2F10%2F108015 J. W. Neuberger C. Feiler H. Maier W. P. Schleich article Paul_2015 Due to the universality of blackbody radiation the constant in the Stefan–Boltzmann law connecting the energy density and temperature of blackbody radiation is either a universal constant, or built out of several universal constants. Since the Stefan–Boltzmann law follows from thermodynamics and classical electrodynamics this constant must involve the speed of light and the Boltzmann constant. However, a dimensional analysis points to the existence of an additional universal constant not present in the two classical theories giving birth to the Stefan–Boltzmann law. In the most elementary version this constant has the dimension of an action and is thereby proportional to Planck’s constant. We point out this unusual phenomenon of the combination of two classical laws creating a quantum law and speculate about its deeper origin. 2015 10 10.1088/0031-8949/2015/t165/014027 Physica Scripta T165 {IOP} Publishing 014027 https://doi.org/10.1088%2F0031-8949%2F2015%2Ft165%2F014027 D. M. Greenberger S. T. Stenholm W. P. Schleich article Schleich_2015 We derive a ‘master’ wave equation for a family of complex-valued waves whose phase dynamics is dictated by the Hamilton–Jacobi equation for the classical action . For a special choice of the dynamics of the amplitude R which eliminates all remnants of classical mechanics associated with our wave equation reduces to the Schrödinger equation. In this case the amplitude satisfies a Schrödinger equation analogous to that of a charged particle in an electromagnetic field where the roles of the scalar and the vector potentials are played by the classical energy and the momentum, respectively. In general this amplitude is complex and thereby creates in addition to the classical phase a quantum phase. Classical statistical mechanics, as described by a classical matter wave, follows from our wave equation when we choose the dynamics of the amplitude such that it remains real for all times. Our analysis shows that classical and quantum matter waves are distinguished by two different choices of the dynamics of their amplitudes rather than two values of Planck’s constant. 2015 9 10.1088/0031-8949/90/10/108009 Physica Scripta 90 {IOP} Publishing 108009 10 https://doi.org/10.1088%2F0031-8949%2F90%2F10%2F108009 W. P. Schleich D. M. Greenberger D. H. Kobe M. O. Scully article Leuchs_2015 We use the P-distribution to show that the familiar values 1, 2 and 3 of the normalized second order correlation function at equal times corresponding to a coherent state, a thermal state and a highly squeezed vacuum are a consequence of the number of dimensions these states take up in quantum phase space. Whereas the thermal state exhibits rotational symmetry and thus extends over two dimensions, the squeezed vacuum factorizes into two independent one-dimensional phase space variables, and in the limit of large squeezing is therefore a one-dimensional object. The coherent state is a point in the phase space of the P-distribution and thus has zero dimensions. The fact that for photon number states the P-distribution is even narrower than that of the zero-dimensional coherent state suggests the notion of ‘negative’ dimensions. 2015 9 10.1088/0031-8949/90/10/108007 Physica Scripta 90 {IOP} Publishing 108007 10 https://doi.org/10.1088%2F0031-8949%2F90%2F10%2F108007 G. Leuchs R. J. Glauber W. P. Schleich article Leuchs_2015 We show that the different values 1, 2 and 3 of the normalized second-order correlation function corresponding to a coherent state, a thermal state and a highly squeezed vacuum originate from the different dimensionality of these states in phase space. In particular, we derive an exact expression for in terms of the ratio of the moments of the classical energy evaluated with the Wigner function of the quantum state of interest and corrections proportional to the reciprocal of powers of the average number of photons. In this way we establish a direct link between and the shape of the state in phase space. Moreover, we illuminate this connection by demonstrating that in the semi-classical limit the familiar photon statistics of a thermal state arise from an area in phase space weighted by a two-dimensional Gaussian, whereas those of a highly squeezed state are governed by a line-integral of a one-dimensional Gaussian. 2015 6 10.1088/0031-8949/90/7/074066 Physica Scripta 90 {IOP} Publishing 074066 7 https://doi.org/10.1088%2F0031-8949%2F90%2F7%2F074066 G. Leuchs R. J. Glauber W. P. Schleich article Feiler_2015 We show that all Dirichlet series, linear combinations of them and their analytical continuations represent probability amplitudes for measurements on time-dependent quantum systems. In particular, we connect an arbitrary Dirichlet series to the time evolution of an appropriately prepared quantum state in a non-linear oscillator with logarithmic energy spectrum. However, the realization of a superposition of two Dirichlet sums and its analytical continuation requires two quantum systems which are entangled, and a joint measurement. We illustrate our approach of implementing arbitrary Dirichlet series in quantum systems using the example of the Riemann zeta function and relate its non-trivial zeros to the interference of two quantum states reminiscent of a Schrödinger cat. 2015 6 10.1088/1367-2630/17/6/063040 New Journal of Physics 17 {IOP} Publishing 063040 6 https://doi.org/10.1088%2F1367-2630%2F17%2F6%2F063040 C. Feiler W. P. Schleich article PhysRevLett.114.063002 2015 2 10.1103/PhysRevLett.114.063002 Phys. Rev. Lett. 114 American Physical Society 063002 https://link.aps.org/doi/10.1103/PhysRevLett.114.063002 P. Berg S. Abend G. Tackmann C. Schubert E. Giese W. P. Schleich F. A. Narducci W. Ertmer E. M. Rasel article D_m_t_r_2015 Scattering of a quantum particle with internal structure is fundamentally different from that of a point particle and shows quantum effects such as the modification of transmission due to tunnelling and trapping of the particle. As in a preceding paper (Shore et al 2014 New J. Phys. 17 013046) we consider a model of a symmetric, rigid rotor travelling through an aperture in a thin but impenetrable screen which is perpendicular to both the direction of motion and the rotation axis. We determine the quantum mechanical properties of this two-dimensional geometrical model using a quasi one-dimensional scattering problem with unconventional boundaries. Our calculations rely on finding the Green's function, which has a direct connection to the scattering matrix. Evaluated on a discrete lattice the Hamiltonian is ‘dressed’ by a self-energy correction that takes into account the open boundary conditions in an exact way. We find that the passage through the aperture can be suppressed or enhanced as a result of the rotational motion. These effects manifest themselves through resonances in the transmission probability as a function of incident energy and symmetry of the incident wavefunction. We determine the density-of-states to reveal the mode structure of resonant states and to exhibit the lifetimes of temporary trapping within the aperture. 2015 2 10.1088/1367-2630/17/2/023044 New Journal of Physics 17 {IOP} Publishing 023044 2 https://doi.org/10.1088%2F1367-2630%2F17%2F2%2F023044 P. Dömötör P. Földi M. G. Benedict B. W. Shore W. P. Schleich article GLEISBERG20152556 We propose a method to factor numbers using a single particle caught in a separable two-dimensional potential with a logarithmic energy spectrum. The particle initially prepared in the ground state is excited with high probability by a sinusoidally time-dependent perturbation into a state whose two quantum numbers represent the factors of a number encoded in the frequency of the perturbation. We discuss the limitations of our method arising from off-resonant transitions and from decoherence. 2015 0375-9601 https://doi.org/10.1016/j.physleta.2015.05.038 Physics Letters A 379 2556 - 2560 40 Number theory, Trapped particle, Factorization protocol http://www.sciencedirect.com/science/article/pii/S0375960115005137 F. Gleisberg M. Volpp W. P. Schleich report 2015 978-3-8047-3343-5 Perspektiven der Quantentechnologien Nationale Akademie der Wissenschaften Leopoldina, acatech - Deutsche Akademie der Technikwissenschaften, Union der deutschen Akademien der Wissenschaften

Halle (Saale)

64 article KLEINERT20151 Light-pulse atom interferometers rely on the wave nature of matter and its manipulation with coherent laser pulses. They are used for precise gravimetry and inertial sensing as well as for accurate measurements of fundamental constants. Reaching higher precision requires longer interferometer times which are naturally encountered in microgravity environments such as drop-tower facilities, sounding rockets and dedicated satellite missions aiming at fundamental quantum physics in space. In all those cases, it is necessary to consider arbitrary trajectories and varying orientations of the interferometer set-up in non-inertial frames of reference. Here we provide a versatile representation-free description of atom interferometry entirely based on operator algebra to address this general situation. We show how to analytically determine the phase shift as well as the visibility of interferometers with an arbitrary number of pulses including the effects of local gravitational accelerations, gravity gradients, the rotation of the lasers and non-inertial frames of reference. Our method conveniently unifies previous results and facilitates the investigation of novel interferometer geometries. 2015 0370-1573 https://doi.org/10.1016/j.physrep.2015.09.004 Physics Reports 605 1 - 50 Atom interferometry, Quantum optics http://www.sciencedirect.com/science/article/pii/S0370157315003968 Representation-free description of light-pulse atom interferometry including non-inertial effects S. Kleinert E. Kajari A. Roura W. P. Schleich article Shore_2015 Classically, rigid objects with elongated shapes can fit through apertures only when properly aligned. Quantum-mechanical particles which have internal structure (e.g. a diatomic molecule) also are affected during attempts to pass through small apertures, but there are interesting differences with classical structured particles. We illustrate here some of these differences for ultra-slow particles. Notably, we predict resonances that correspond to prolonged delays of the rotor within the aperture—a trapping phenomenon not found classically. 2015 1 10.1088/1367-2630/17/1/013046 New Journal of Physics 17 {IOP} Publishing 013046 1 https://doi.org/10.1088%2F1367-2630%2F17%2F1%2F013046 B. W. Shore P. Dömötör E. Sadurní G. Süßmann W. P. Schleich article Roura_2014 Long-time atom interferometry is instrumental to various high-precision measurements of fundamental physical properties, including tests of the equivalence principle. Due to rotations and gravity gradients, the classical trajectories characterizing the motion of the wave packets for the two branches of the interferometer do not close in phase space, an effect which increases significantly with the interferometer time. The relative displacement between the interfering wave packets in such open interferometers leads to a fringe pattern in the density profile at each exit port and a loss of contrast in the oscillations of the integrated particle number as a function of the phase shift. Paying particular attention to gravity gradients, we present a simple mitigation strategy involving small changes in the timing of the laser pulses which is very easy to implement. A useful representation-free description of the state evolution in an atom interferometer is introduced and employed to analyze the loss of contrast and mitigation strategy in the general case. (As a by-product, a remarkably compact derivation of the phase-shift in a general light-pulse atom interferometer is provided.) Furthermore, exact results are obtained for (pure and mixed) Gaussian states which allow a simple interpretation in terms of the alignment of Wigner functions in phase-space. Analytical results are also obtained for expanding Bose–Einstein condensates within the time-dependent Thomas–Fermi approximation. Finally, a combined strategy for rotations and nonaligned gravity gradients is considered as well. 2014 12 10.1088/1367-2630/16/12/123012 New Journal of Physics 16 {IOP} Publishing 123012 12 https://doi.org/10.1088%2F1367-2630%2F16%2F12%2F123012 A. Roura W. Zeller W. P. Schleich article Neuberger_2014 A great many phenomena in physics can be traced back to the zeros of a function or a functional. Eigenvalue or variational problems prevalent in classical as well as quantum mechanics are examples illustrating this statement. Continuous descent methods taken with respect to the proper metric are efficient ways to attack such problems. In particular, the continuous Newton method brings out the lines of constant phase of a complex-valued function. Although the patterns created by the Newton flow are reminiscent of the field lines of electrostatics and magnetostatics they cannot be realized in this way since in general they are not curl-free. We apply the continuous Newton method to the Riemann zeta function and discuss the emerging patterns emphasizing especially the structuring of the non-trivial zeros by the separatrices. This approach might open a new road toward the Riemann hypothesis. 2014 10 10.1088/1367-2630/16/10/103023 New Journal of Physics 16 {IOP} Publishing 103023 10 https://doi.org/10.1088%2F1367-2630%2F16%2F10%2F103023 J. W. Neuberger C. Feiler H. Maier W. P. Schleich article PhysRevLett.112.203002 2014 5 10.1103/PhysRevLett.112.203002 Phys. Rev. Lett. 112 American Physical Society 203002 https://link.aps.org/doi/10.1103/PhysRevLett.112.203002 D. Schlippert J. Hartwig H. Albers L. L. Richardson C. Schubert A. Roura W. P. Schleich W. Ertmer E. M. Rasel article Aguilera_2014 The theory of general relativity describes macroscopic phenomena driven by the influence of gravity while quantum mechanics brilliantly accounts for microscopic effects. Despite their tremendous individual success, a complete unification of fundamental interactions is missing and remains one of the most challenging and important quests in modern theoretical physics. The spacetime explorer and quantum equivalence principle space test satellite mission, proposed as a medium-size mission within the Cosmic Vision program of the European Space Agency (ESA), aims for testing general relativity with high precision in two experiments by performing a measurement of the gravitational redshift of the Sun and the Moon by comparing terrestrial clocks, and by performing a test of the universality of free fall of matter waves in the gravitational field of Earth comparing the trajectory of two Bose–Einstein condensates of 85Rb and 87Rb. The two ultracold atom clouds are monitored very precisely thanks to techniques of atom interferometry. This allows to reach down to an uncertainty in the Eötvös parameter of at least 2 × 10−15. In this paper, we report about the results of the phase A mission study of the atom interferometer instrument covering the description of the main payload elements, the atomic source concept, and the systematic error sources. 2014 5 10.1088/0264-9381/31/11/115010 Classical and Quantum Gravity 31 {IOP} Publishing 115010 11 https://doi.org/10.1088%2F0264-9381%2F31%2F11%2F115010 D. N. Aguilera H. Ahlers B. Battelier A. Bawamia A. Bertoldi R. Bondarescu K. Bongs P. Bouyer C. Braxmaier L. Cacciapuoti C. Chaloner M. Chwalla W. Ertmer M. Franz N. Gaaloul M. Gehler D. Gerardi L. Gesa N. Gürlebeck J. Hartwig M. Hauth O. Hellmig W. Herr S. Herrmann A. Heske A. Hinton P. Ireland P. Jetzer U. Johann M. Krutzik A. Kubelka C. Lämmerzahl A. Landragin I. Lloro D. Massonnet I. Mateos A. Milke M. Nofrarias M. Oswald K. Posso-Trujillo E. Rasel E. Rocco A. Roura J. Rudolph W. Schleich C. Schubert T. Schuldt S. Seidel K. Sengstock C. F. Sopuerta F. Sorrentino D. Summers G. M. Tino C. Trenkel N. Uzunoglu W. Klitzing R. Walser T. Wendrich A. Wenzlawski P. Weßels A. Wicht E. Wille M. Williams P. Windpassinger N. Zahzam inproceedings 2014 Proceedings of FEL 2014

Basel

353-357 R. Endrich E. Giese P. Kling R. Sauerbrey W. P. Schleich inproceedings 2014 Proceedings of FEL 2014

Basel

348-352 P. Kling R. Endrich E. Giese R. Sauerbrey W. P. Schleich inproceedings 2014 10.3254/978-1-61499-448-0-171 Atom Interferometry 188 IOS Press

Amsterdam, Oxford, Tokyo, Washington DC

Proceedings of the International School of Physics "Enrico Fermi" G. M. Tino and M. A. Kasevich 171-236 E. Giese W. Zeller S. Kleinert M. Meister V. Tamma A. Roura W. P. Schleich article 2014 Physics 7 39 W. P. Schleich E. Rasel article PhysRevA.88.053608 2013 11 10.1103/PhysRevA.88.053608 Phys. Rev. A 88 American Physical Society 053608 https://link.aps.org/doi/10.1103/PhysRevA.88.053608 E. Giese A. Roura G. Tackmann E. M. Rasel W. P. Schleich article PhysRevA.88.043623 2013 10 10.1103/PhysRevA.88.043623 Phys. Rev. A 88 American Physical Society 043623 https://link.aps.org/doi/10.1103/PhysRevA.88.043623 C. T. Weiß P. V. Mironova J. Fortágh W. P. Schleich R. Walser article PhysRevLett.111.113201 2013 9 10.1103/PhysRevLett.111.113201 Phys. Rev. Lett. 111 American Physical Society 113201 https://link.aps.org/doi/10.1103/PhysRevLett.111.113201 M. A. Efremov L. Plimak M. Yu. Ivanov W. P. Schleich article Feiler_2013 We propose measurements on a quantum system to realize the Riemann zeta function ζ. A single system, that is classical interference, suffices to create the Dirichlet representation of ζ. In contrast, we need measurements performed on two entangled quantum systems to extend ζ into the critical strip of complex space where the non-trivial zeros of ζ are located. As a consequence, we can view these zeros as a result of a Schrödinger cat which is by its very construction similar to, but in its details very different from, the superposition formed by two coherent states of identical amplitudes but opposite phases. This interpretation suggests that entanglement in quantum mechanics is the analogue of analytic continuation of complex analysis. 2013 6 10.1088/1367-2630/15/6/063009 New Journal of Physics 15 {IOP} Publishing 063009 6 https://doi.org/10.1088%2F1367-2630%2F15%2F6%2F063009 C. Feiler W. P. Schleich article Heim_2013 We propose a tunable macroscopic quantum system based on two fractional vortices. Our analysis shows that two coupled fractional vortices pinned at two artificially created κ discontinuities of the Josephson phase in a long Josephson junction can reach the quantum regime where coherent quantum oscillations arise. For this purpose we map the dynamics of this system to that of a single particle in a double-well potential. By tuning the κ discontinuities with injector currents, we are able to control the parameters of the effective double-well potential as well as to prepare a desired state of the fractional vortex molecule. The values of the parameters derived from this model suggest that an experimental realization of this tunable macroscopic quantum system is possible with today's technology. 2013 5 10.1088/1367-2630/15/5/053020 New Journal of Physics 15 {IOP} Publishing 053020 5 https://doi.org/10.1088%2F1367-2630%2F15%2F5%2F053020 D. M. Heim K. Vogel W. P. Schleich D. Koelle R. Kleiner E. Goldobin article PhysRevE.87.042912 2013 4 10.1103/PhysRevE.87.042912 Phys. Rev. E 87 American Physical Society 042912 https://link.aps.org/doi/10.1103/PhysRevE.87.042912 S. Bittner B. Dietz M. Miski-Oglu A. Richter C. Ripp E. Sadurní W. P. Schleich article PhysRevA.87.023604 2013 2 10.1103/PhysRevA.87.023604 Phys. Rev. A 87 American Physical Society 023604 https://link.aps.org/doi/10.1103/PhysRevA.87.023604 M. A. Efremov P. V. Mironova W. P. Schleich article PhysRevA.87.023405 2013 2 10.1103/PhysRevA.87.023405 Phys. Rev. A 87 American Physical Society 023405 https://link.aps.org/doi/10.1103/PhysRevA.87.023405 Z. Liao M. Al-Amri Th. Becker W. P. Schleich M. O. Scully M. S. Zubairy article PhysRevA.87.021602 2013 2 10.1103/PhysRevA.87.021602 Phys. Rev. A 87 American Physical Society 021602 https://link.aps.org/doi/10.1103/PhysRevA.87.021602 M. Grupp W. P. Schleich E. Goldobin D. Koelle R. Kleiner R. Walser article Gleisberg_2013 We propose a method to factor numbers based on the quantum dynamics of two interacting bosonic atoms where the single-particle energy spectrum depends logarithmically on the quantum number. We show that two atoms initially prepared in the ground state are preferentially excited by a time-dependent interaction into a two-particle energy state characterized by the factors. Hence, a measurement of the energy of one of the two atoms yields the factors. The number to be factored is encoded in the frequency of a sinusoidally modulated interaction. We also discuss the influence of off-resonant transitions and the limitation of the number to be factored imposed by experimental conditions. 2013 2 10.1088/1367-2630/15/2/023037 New Journal of Physics 15 {IOP} Publishing 023037 2 https://doi.org/10.1088%2F1367-2630%2F15%2F2%2F023037 F. Gleisberg R. Mack K. Vogel W. P. Schleich article PhysRevLett.110.093602 2013 2 10.1103/PhysRevLett.110.093602 Phys. Rev. Lett. 110 American Physical Society 093602 https://link.aps.org/doi/10.1103/PhysRevLett.110.093602 H. Müntinga H. Ahlers M. Krutzik A. Wenzlawski S. Arnold D. Becker K. Bongs H. Dittus H. Duncker N. Gaaloul C. Gherasim E. Giese C. Grzeschik T. W. Hänsch O. Hellmig W. Herr S. Herrmann E. Kajari S. Kleinert C. Lämmerzahl W. Lewoczko-Adamczyk J. Malcolm N. Meyer R. Nolte J. Reichel A. Roura J. Rudolph M. Schiemangk S. T. Seidel K. Sengstock V. Tamma T. Valenzuela A. Vogel R. Walser T. Wendrich P. Windpassinger W. Zeller T. Zoest W. Ertmer W. P. Schleich E. M. Rasel article Schleich_2013 Motivated by a recent claim by Müller et al (2010 Nature 463 926–9) that an atom interferometer can serve as an atom clock to measure the gravitational redshift with an unprecedented accuracy, we provide a representation-free description of the Kasevich–Chu interferometer based on operator algebra. We use this framework to show that the operator product determining the number of atoms at the exit ports of the interferometer is a c-number phase factor whose phase is the sum of only two phases: one is due to the acceleration of the phases of the laser pulses and the other one is due to the acceleration of the atom. This formulation brings out most clearly that this interferometer is an accelerometer or a gravimeter. Moreover, we point out that in different representations of quantum mechanics such as the position or the momentum representation the phase shift appears as though it originates from different physical phenomena. Due to this representation dependence conclusions concerning an enhanced accuracy derived in a specific representation are unfounded. 2013 1 10.1088/1367-2630/15/1/013007 New Journal of Physics 15 {IOP} Publishing 013007 1 https://doi.org/10.1088%2F1367-2630%2F15%2F1%2F013007 W. P. Schleich D. M. Greenberger E. M. Rasel article doi:10.1080/09500340.2012.746400 2013 10.1080/09500340.2012.746400 Journal of Modern Optics 60 Taylor & Francis 86-94 1 R. Menzel A. Heuer D. Puhlmann K. Dechoum M. Hillery M. J. A. Spähn W. P. Schleich article PhysRevA.87.013627 2013 1 10.1103/PhysRevA.87.013627 Phys. Rev. A 87 American Physical Society 013627 https://link.aps.org/doi/10.1103/PhysRevA.87.013627 P. V. Mironova M. A. Efremov W. P. Schleich article Kazemi_2013 Quantum carpets—the spatio-temporal de Broglie density profiles—woven by an atom or an electron in the near-field region of a diffraction grating bring to light, in real time, the decoherence of each individual component of the interference term of the Wigner function characteristic of superposition states. The proposed experiments are feasible with present-day technology. 2013 1 10.1088/1367-2630/15/1/013052 New Journal of Physics 15 {IOP} Publishing 013052 1 https://doi.org/10.1088%2F1367-2630%2F15%2F1%2F013052 P. Kazemi S. Chaturvedi I. Marzoli R. F. O'Connell W. P. Schleich article PhysRevA.87.014102 2013 1 10.1103/PhysRevA.87.014102 Phys. Rev. A 87 American Physical Society 014102 https://link.aps.org/doi/10.1103/PhysRevA.87.014102 W. P. Schleich M. Freyberger M. S. Zubairy article PhysRevLett.110.010401 2013 1 10.1103/PhysRevLett.110.010401 Phys. Rev. Lett. 110 American Physical Society 010401 https://link.aps.org/doi/10.1103/PhysRevLett.110.010401 W. P. Schleich D. M. Greenberger E. M. Rasel article Schleich5374 The time-dependent Schrödinger equation is a cornerstone of quantum physics and governs all phenomena of the microscopic world. However, despite its importance, its origin is still not widely appreciated and properly understood. We obtain the Schrödinger equation from a mathematical identity by a slight generalization of the formulation of classical statistical mechanics based on the Hamilton{\textendash}Jacobi equation. This approach brings out most clearly the fact that the linearity of quantum mechanics is intimately connected to the strong coupling between the amplitude and phase of a quantum wave. 2013 0027-8424 10.1073/pnas.1302475110 Proceedings of the National Academy of Sciences 110 National Academy of Sciences 5374--5379 14 W. P. Schleich D. M. Greenberger D. H. Kobe M. O. Scully inproceedings 2013 Proceedings of FEL 2013, Nara, Japan JACoW T. Tanaka and V. R. W. Schaa P. Preiss R. Sauerbrey M. S. Zubairy R. Endrich E. Giese P. Kling M. Knobl W. P. Schleich article HEIM20131822 We analyze the tunneling of a particle through a repulsive potential resulting from an inverted harmonic oscillator in the quantum mechanical phase space described by the Wigner function. In particular, we solve the partial differential equations in phase space determining the Wigner function of an energy eigenstate of the inverted oscillator. The reflection or transmission coefficients R or T are then given by the total weight of all classical phase-space trajectories corresponding to energies below, or above the top of the barrier given by the Wigner function. 2013 0375-9601 10.1016/j.physleta.2013.05.017 Physics Letters A 377 1822 - 1825 31 Tunneling, Inverted oscillator, Wigner function http://www.sciencedirect.com/science/article/pii/S0375960113004878 D. M. Heim W. P. Schleich P. M. Alsing J. P. Dahl S. Varro article Buser_2013 The standard model of modern cosmology, which is based on the Friedmann–Lemaître–Robertson–Walker metric, allows the definition of an absolute time. However, there exist (cosmological) models consistent with the theory of general relativity for which such a definition cannot be given since they offer the possibility for time travel. The simplest of these models is the cosmological solution discovered by Kurt Gödel, which describes a homogeneous, rotating universe. Disregarding the paradoxes that come along with the abolishment of causality in such space–times, we are interested in the purely academic question of how an observer would visually perceive the time travel of an object in Gödel's universe. For this purpose, we employ the technique of ray tracing, a standard tool in computer graphics, and visualize various scenarios to bring out the optical effects experienced by an observer located in this universe. In this way, we provide a new perspective on the space–time structure of Gödel's model. 2013 1 10.1088/1367-2630/15/1/013063 New Journal of Physics 15 {IOP} Publishing 013063 1 https://doi.org/10.1088%2F1367-2630%2F15%2F1%2F013063 M. Buser E. Kajari W. P. Schleich article Case:12 We examine the free time evolution of a rectangular one dimensional Schr\"{o}dinger wave packet of constant phase during the early stage which in the paraxial wave approximation is identical to the diffraction of a scalar field from a single slit. Our analysis, based on numerics and the Cornu spiral reveals considerable intricate detail behavior in the density and phase of the wave. We also point out a concentration of the intensity that occurs on axis and propose a new measure of width that expresses this concentration. 2012 12 10.1364/OE.20.027253 Opt. Express 20 OSA 27253--27262 25 Diffraction; Diffraction theory; Diffraction limit; Evanescent waves; Light fields; Phase space analysis methods; Ptychography; Talbot effect http://www.opticsexpress.org/abstract.cfm?URI=oe-20-25-27253 W. B. Case E. Sadurní W. P. Schleich article PhysRevA.86.063622 2012 12 10.1103/PhysRevA.86.063622 Phys. Rev. A 86 American Physical Society 063622 https://link.aps.org/doi/10.1103/PhysRevA.86.063622 D. M. Greenberger W. P. Schleich E. M. Rasel article Plimak_2012 A formal implementation of the concepts of mesoscopic electromagnetic interaction and of the propagating wave in quantum electrodynamics beyond the rotating wave approximation is discussed. Used as a guide, these concepts lead to a natural resolution of a long-standing controversy: causality violations in the Glauber–Kelley–Kleiner photodetection theory. The Glauber–Kelley–Kleiner definition of the time-normal operator ordering must be amended without the rotating wave approximation, which eliminates all causality problems. 2012 2 10.1088/0031-8949/2012/t147/014026 Physica Scripta T147 {IOP} Publishing 014026 https://doi.org/10.1088%2F0031-8949%2F2012%2Ft147%2F014026 L. I. Plimak S. T. Stenholm W. P. Schleich article W_lk_2012 We propose two algorithms to factor numbers using Gauss sums and entanglement: (i) in a Shor-like algorithm we encode the standard Gauss sum in one of two entangled states and (ii) in an interference algorithm we create a superposition of Gauss sums in the probability amplitudes of two entangled states. These schemes are rather efficient provided that there exists a fast algorithm that can detect a period of a function hidden in its zeros. 2012 1 10.1088/1367-2630/14/1/013049 New Journal of Physics 14 {IOP} Publishing 013049 1 https://doi.org/10.1088%2F1367-2630%2F14%2F1%2F013049 S. Wölk W. P. Schleich article Tamma2012 The phase $\phi$ of any wave is determined by the ratio x/$\lambda$ consisting of the distance x propagated by the wave and its wavelength $\lambda$. Hence, the dependence of $\phi$ on $\lambda$ constitutes an analogue system for the mathematical operation of division, that is to obtain the hyperbolic function f($\xi$)≡1/$\xi$. We take advantage of this observation to decompose integers into primes and implement this approach towards factorization of numbers in a multi-path Michelson interferometer. This work is part of a larger program geared towards unraveling the connections between quantum mechanics and number theory. We briefly summarize this aspect. 2012 1 01 1572-9516 10.1007/s10701-010-9522-3 Foundations of Physics 42 111--121 1 https://doi.org/10.1007/s10701-010-9522-3 V. Tamma C. O. Alley W. P. Schleich Y. H. Shih inbook Woelk2012 In this paper, we connect our approach of factoring numbers using the continuous truncated Gauss sum (W{"o}lk et al., J. Mod. Optic, 2009) with the phenomenon of quantum carpets. In particular, we demonstrate that the degree of degeneracy of the ratio ℓ ∕ N translates into a crossing of the canals and ridges contained in the design of quantum carpets. In this way, quantum carpets represent an experimental implementation of our idea of factorization with degeneracies. 2012 978-1-4419-6624-7 10.1007/978-1-4419-6624-7_18 Springer US

Boston, MA

L. Cohen, H. V. Poor and M. O. Scully 259--269 https://doi.org/10.1007/978-1-4419-6624-7_18 S. Wölk W. P. Schleich article Menzel9314 The precise knowledge of one of two complementary experimental outcomes prevents us from obtaining complete information about the other one. This formulation of Niels Bohr{\textquoteright}s principle of complementarity when applied to the paradigm of wave-particle dualism{\textemdash}that is, to Young{\textquoteright}s double-slit experiment{\textemdash}implies that the information about the slit through which a quantum particle has passed erases interference. In the present paper we report a double-slit experiment using two photons created by spontaneous parametric down-conversion where we observe interference in the signal photon despite the fact that we have located it in one of the slits due to its entanglement with the idler photon. This surprising aspect of complementarity comes to light by our special choice of the TEM01 pump mode. According to quantum field theory the signal photon is then in a coherent superposition of two distinct wave vectors giving rise to interference fringes analogous to two mechanical slits. 2012 0027-8424 10.1073/pnas.1201271109 Proceedings of the National Academy of Sciences 109 National Academy of Sciences 9314--9319 24 R. Menzel D. Puhlmann A. Heuer W. P. Schleich article Sorrentino_2011 This paper presents the current status and future prospects of the Space Atom Interferometer project (SAI), funded by the European Space Agency. Atom interferometry provides extremely sensitive and accurate tools for the measurement of inertial forces. Operation of atom interferometers in microgravity is expected to enhance the performance of such sensors. Main goal of SAI is to demonstrate the possibility of placing atom interferometers in space. The resulting drop-tower compatible atom interferometry acceleration sensor prototype is described. Expected performance limits and potential scientific applications in a micro-gravity environment are also discussed. 2011 12 10.1088/1742-6596/327/1/012050 Journal of Physics: Conference Series 327 {IOP} Publishing 012050 https://doi.org/10.1088%2F1742-6596%2F327%2F1%2F012050 F. Sorrentino K. Bongs P. Bouyer L. Cacciapuoti M. Angelis H. Dittus W. Ertmer J. Hartwig M. Hauth S. Herrmann K. Huang M. Inguscio E. Kajari T. Könemann C. Lämmerzahl A. Landragin G. Modugno F. Pereira Santos M. Prevedelli E. M. Rasel W. P. Schleich M. Schmidt A. Senger K. Sengstock G. Stern G. M. Tino T. Valenzuela R. Walser P. Windpassinger article W_lk_2011 We use the periodicity properties of generalized Gauss sums to factor numbers. Moreover, we derive rules for finding the factors and illustrate this factorization scheme for various examples. This algorithm relies solely on interference and scales exponentially. 2011 10 10.1088/1367-2630/13/10/103007 New Journal of Physics 13 {IOP} Publishing 103007 10 https://doi.org/10.1088%2F1367-2630%2F13%2F10%2F103007 S. Wölk W. Merkel W. P. Schleich I. Sh. Averbukh B. Girard article Merkel_2011 We propose three implementations of the Gauss sum factorization schemes discussed in part I of this series (Wölk et al 2011 New J. Phys. 13 103007): (i) a two-photon transition in a multi-level ladder system induced by a chirped laser pulse, (ii) a chirped one-photon transition in a two-level atom with a periodically modulated excited state and (iii) a linearly chirped one-photon transition driven by a sequence of ultrashort pulses. For each of these quantum systems, we show that the excitation probability amplitude is given by an appropriate Gauss sum. We provide rules on how to encode the number N to be factored in our system and how to identify the factors of N in the fluorescence signal of the excited state. 2011 10 10.1088/1367-2630/13/10/103008 New Journal of Physics 13 {IOP} Publishing 103008 10 https://doi.org/10.1088%2F1367-2630%2F13%2F10%2F103008 W. Merkel S. Wölk W. P. Schleich I. Sh. Averbukh B. Girard G. G. Paulus article Rudolph2011 Clouds of ultra-cold atoms and especially Bose--Einstein condensates (BEC) provide a source for coherent matter-waves in numerous earth bound experiments. Analogous to optical interferometry, matter-wave interferometers can be used for precision measurements allowing for a sensitivity orders of magnitude above their optical counterparts. However, in some respects the presence of gravitational forces in the lab limits experimental possibilities. In this article, we report about a compact and robust experiment generating Bose--Einstein condensates in the drop tower facility in Bremen, Germany. We also present the progress of building the succeeding experiment in which a two species atom interferometer will be implemented to test the weak equivalence principle with quantum matter. 2011 6 01 1875-0494 10.1007/s12217-010-9247-0 Microgravity Science and Technology 23 287--292 3 https://doi.org/10.1007/s12217-010-9247-0 J. Rudolph N. Gaaloul Y. Singh H. Ahlers W. Herr T. A. Schulze S. T. Seidel C. Rode V. Schkolnik W. Ertmer E. M. Rasel H. Müntinga T. Könemann A. Resch S. Herrmann C. Lämmerzahl T. Zoest H. Dittus A. Vogel A. Wenzlawski K. Sengstock N. Meyer K. Bongs M. Krutzik W. Lewoczko-Adamczyk M. Schiemangk M. Eckart E. Kajari S. Arnold G. Nandi W. P. Schleich R. Walser T. W. Hänsch J. Reichel article PhysRevA.83.051602 2011 5 10.1103/PhysRevA.83.051602 Phys. Rev. A 83 American Physical Society 051602 https://link.aps.org/doi/10.1103/PhysRevA.83.051602 S. Zippilli B. Mohring G. Morigi W. Schleich article PhysRevA.83.020304 2011 2 10.1103/PhysRevA.83.020304 Phys. Rev. A 83 American Physical Society 020304 https://link.aps.org/doi/10.1103/PhysRevA.83.020304 V. Tamma X. He A. Garuccio W. P. Schleich Y. Shih inproceedings Wolk:11 We suggest a way to determine the Riemann zeta function with the help of quantum mechanics. Furthermore, we discuss the factoring abilities of Gauss sums and introduce a way to calculate them with the help of entanglement. 2011 10.1364/ICQI.2011.QMC1 International Conference on Quantum Information International Conference on Quantum Information Optical Society of America QMC1 Quantum optics; Quantum information and processing ; Beam splitters; Bose Einstein condensates; Cavity quantum electrodynamics; Cold atoms; Destructive interference; Quantum electronics http://www.osapublishing.org/abstract.cfm?URI=ICQI-2011-QMC1 S. Wölk C. Feiler W. P. Schleich article Sorrentino2010 Atom interferometry represents a quantum leap in the technology for the ultra-precise monitoring of accelerations and rotations and, therefore, for the science that relies on these quantities. These sensors evolved from a new kind of optics based on matter-waves rather than light-waves and might result in an advancement of the fundamental detection limits by several orders of magnitude. This paper describes the current status of the Space Atom Interferometer project (SAI), funded by the European Space Agency. In a multi-pronged approach, SAI aims to investigate both experimentally and theoretically the various aspects of placing atom interferometers in space: the equipment needs, the realistically expected performance limits and potential scientific applications in a micro-gravity environment considering all aspects of quantum, relativistic and metrological sciences. A drop-tower compatible atom interferometry acceleration sensor prototype has been designed, and the manufacturing of its subsystems has been started. A compact modular laser system for cooling and trapping rubidium atoms has been assembled. A compact Raman laser module, featuring outstandingly low phase noise, has been realized. Possible schemes to implement coherent atomic sources in the atom interferometer have been experimentally demonstrated. 2010 10 01 1875-0494 10.1007/s12217-010-9240-7 Microgravity Science and Technology 22 551--561 4 https://doi.org/10.1007/s12217-010-9240-7 F. Sorrentino K. Bongs Ph. Bouyer L. Cacciapuoti M. Angelis H. Dittus W. Ertmer A. Giorgini J. Hartwig M. Hauth S. Herrmann M. Inguscio E. Kajari T. T. Könemann C. Lämmerzahl A. Landragin G. Modugno F. Santos M. Prevedelli E. M. Rasel W. P. Schleich M. Schmidt A. Senger K. Sengstock G. Stern G. M. Tino R. Walser article Glauber_2010 We derive the complete photon count statistics of an interferometer based on two beam splitters. As a special case we consider a joint intensity–electric field measurement. Our approach is based on the transformation properties of state vectors as well as field operators at a beam splitter. 2010 9 10.1088/0031-8949/2010/t140/014002 Physica Scripta T140 {IOP} Publishing 014002 https://doi.org/10.1088%2F0031-8949%2F2010%2Ft140%2F014002 R. J. Glauber L. A. Orozco K. Vogel W. P. Schleich H. Walther article PhysRevA.82.032119 2010 9 10.1103/PhysRevA.82.032119 Phys. Rev. A 82 American Physical Society 032119 https://link.aps.org/doi/10.1103/PhysRevA.82.032119 R. Mack J. P. Dahl H. Moya-Cessa W. T. Strunz R. Walser W. P. Schleich article Kajari2010 We show that in complete agreement with classical mechanics, the dynamics of any quantum mechanical wave packet in a linear gravitational potential involves the gravitational and the inertial mass only as their ratio. In contrast, the spatial modulation of the corresponding energy wave function is determined by the third root of the product of the two masses. Moreover, the discrete energy spectrum of a particle constrained in its motion by a linear gravitational potential and an infinitely steep wall depends on the inertial as well as the gravitational mass with different fractional powers. This feature might open a new avenue in quantum tests of the universality of free fall. 2010 7 01 1432-0649 10.1007/s00340-010-4085-8 Applied Physics B 100 43--60 1 https://doi.org/10.1007/s00340-010-4085-8 E. Kajari N. L. Harshman E. M. Rasel S. Stenholm G. Süßmann W. P. Schleich article Schmidt_Kaler_2010 Atom optics employs the modern techniques of quantum optics and laser cooling to enable applications which often outperform current standard technologies. Atomic matter wave interferometers allow for ultra-precise sensors; metrology and clocks are pushed to an extraordinary accuracy of 17 digits using single atoms. Miniaturization and integration are driven forward for both atomic clocks and atom optical circuits. With the miniaturization of information-storage and -processing devices, the scale of single atoms is approached in solid state devices, where the laws of quantum physics lead to novel, advantageous features and functionalities. An upcoming branch of atom optics is the control of single atoms, potentially allowing solid state devices to be built atom by atom; some of which would be applicable in future quantum information processing devices. Selective manipulation of individual atoms also enables trace analysis of extremely rare isotopes. Additionally, sources of neutral atoms with high brightness are being developed and, if combined with photo ionization, even novel focused ion beam sources are within reach. Ultracold chemistry is fertilized by atomic techniques, when reactions of chemical constituents are investigated between ions, atoms, molecules, trapped or aligned in designed fields and cooled to ultra-low temperatures such that the reaction kinetics can be studied in a completely state-resolved manner. Focus on Atom Optics and its Applications Contents Sensitive gravity-gradiometry with atom interferometry: progress towards an improved determination of the gravitational constant F Sorrentino, Y-H Lien, G Rosi, L Cacciapuoti, M Prevedelli and G M Tino A single-atom detector integrated on an atom chip: fabrication, characterization and application D Heine, W Rohringer, D Fischer, M Wilzbach, T Raub, S Loziczky, XiYuan Liu, S Groth, B Hessmo and J Schmiedmayer Interaction of a propagating guided matter wave with a localized potential G L Gattobigio, A Couvert, B Georgeot and D Guéry-Odelin Analysis of the entanglement between two individual atoms using global Raman rotations A Gaëtan, C Evellin, J Wolters, P Grangier, T Wilk and A Browaeys Spin polarization transfer in ground and metastable helium atom collisions D Vrinceanu and H R Sadeghpour A fiber Fabry–Perot cavity with high finesse D Hunger, T Steinmetz, Y Colombe, C Deutsch, T W Hänsch and J Reichel Atomic wave packets in amplitude-modulated vertical optical lattices A Alberti, G Ferrari, V V Ivanov, M L Chiofalo and G M Tino Atom interferometry with trapped Bose–Einstein condensates: impact of atom–atom interactions Julian Grond, Ulrich Hohenester, Igor Mazets and Jörg Schmiedmayer Storage of protonated water clusters in a biplanar multipole rf trap C Greve, M Kröner, S Trippel, P Woias, R Wester and M Weidemüller Single-atom detection on a chip: from realization to application A Stibor, H Bender, S Kühnhold, J Fortágh, C Zimmermann and A Günther Ultracold atoms as a target: absolute scattering cross-section measurements P Würtz, T Gericke, A Vogler and H Ott Entanglement-assisted atomic clock beyond the projection noise limit Anne Louchet-Chauvet, Jürgen Appel, Jelmer J Renema, Daniel Oblak, Niels Kjaergaard and Eugene S Polzik Towards the realization of atom trap trace analysis for 39Ar J Welte, F Ritterbusch, I Steinke, M Henrich, W Aeschbach-Hertig and M K Oberthaler Resonant superfluidity in an optical lattice I Titvinidze, M Snoek and W Hofstetter Interference of interacting matter waves Mattias Gustavsson, Elmar Haller, Manfred J Mark, Johann G Danzl, Russell Hart, Andrew J Daley and Hanns-Christoph Nägerl Magnetic trapping of NH molecules with 20 s lifetimes E Tsikata, W C Campbell, M T Hummon, H-I Lu and J M Doyle Imprinting patterns of neutral atoms in an optical lattice using magnetic resonance techniques Michal Karski, Leonid Förster, Jai-Min Choi, Andreas Steffen, Noomen Belmechri, Wolfgang Alt, Dieter Meschede and Artur Widera Frequency stability of optical lattice clocks Jérôme Lodewyck, Philip G Westergaard, Arnaud Lecallier, Luca Lorini and Pierre Lemonde Ultracold quantum gases in triangular optical lattices C Becker, P Soltan-Panahi, J Kronjäger, S Dörscher, K Bongs and K Sengstock Cold atoms near superconductors: atomic spin coherence beyond the Johnson noise limit B Kasch, H Hattermann, D Cano, T E Judd, S Scheel, C Zimmermann, R Kleiner, D Koelle and J Fortágh Focusing a deterministic single-ion beam Wolfgang Schnitzler, Georg Jacob, Robert Fickler, Ferdinand Schmidt-Kaler and Kilian Singer Tuning the structural and dynamical properties of a dipolar Bose–Einstein condensate: ripples and instability islands M Asad-uz-Zaman and D Blume Double-resonance lineshapes in a cell with wall coating and buffer gas Svenja Knappe and Hugh G Robinson Transport and interaction blockade of cold bosonic atoms in a triple-well potential P Schlagheck, F Malet, J C Cremon and S M Reimann Fabrication of a planar micro Penning trap and numerical investigations of versatile ion positioning protocols M Hellwig, A Bautista-Salvador, K Singer, G Werth and F Schmidt-Kaler Laser cooling of a magnetically guided ultracold atom beam A Aghajani-Talesh, M Falkenau, V V Volchkov, L E Trafford, T Pfau and A Griesmaier Creation efficiency of nitrogen-vacancy centres in diamond S Pezzagna, B Naydenov, F Jelezko, J Wrachtrup and J Meijer Top-down pathways to devices with few and single atoms placed to high precision Jessica A Van Donkelaar, Andrew D Greentree, Andrew D C Alves, Lenneke M Jong, Lloyd C L Hollenberg and David N Jamieson Enhanced electric field sensitivity of rf-dressed Rydberg dark states M G Bason, M Tanasittikosol, A Sargsyan, A K Mohapatra, D Sarkisyan, R M Potvliege and C S Adams 2010 6 10.1088/1367-2630/12/6/065014 New Journal of Physics 12 {IOP} Publishing 065014 6 https://doi.org/10.1088%2F1367-2630%2F12%2F6%2F065014 T. Pfau P. Schmelcher W. Schleich article PhysRevB.81.054514 2010 2 10.1103/PhysRevB.81.054514 Phys. Rev. B 81 American Physical Society 054514 https://link.aps.org/doi/10.1103/PhysRevB.81.054514 E. Goldobin K. Vogel W. P. Schleich D. Koelle R. Kleiner article vanZoest1540 Two pillars of modern physics are quantum mechanics and general relativity. So far, both have remained apart with no quantum mechanical description of gravity available. Van Zoest et al. (p. 1540; see the Perspective by Nussenzveig and Barata) present work with a macroscopic quantum mechanical system{\textemdash}a Bose-Einstein condensate (BEC) of rubidium atoms in which the cloud of atoms is cooled into a collective quantum state{\textemdash}in microgravity. By dropping the BEC down a 146-meter-long drop chamber and monitoring the expansion of the quantum gas under these microgravity conditions, the authors provide a proof-of-principle demonstration of a technique that can probe the boundary of quantum mechanics and general relativity and perhaps offer the opportunity to reconcile the two experimentally.Albert Einstein{\textquoteright}s insight that it is impossible to distinguish a local experiment in a {\textquotedblleft}freely falling elevator{\textquotedblright} from one in free space led to the development of the theory of general relativity. The wave nature of matter manifests itself in a striking way in Bose-Einstein condensates, where millions of atoms lose their identity and can be described by a single macroscopic wave function. We combine these two topics and report the preparation and observation of a Bose-Einstein condensate during free fall in a 146-meter-tall evacuated drop tower. During the expansion over 1 second, the atoms form a giant coherent matter wave that is delocalized on a millimeter scale, which represents a promising source for matter-wave interferometry to test the universality of free fall with quantum matter. 2010 0036-8075 10.1126/science.1189164 Science 328 American Association for the Advancement of Science 1540--1543 5985 T. Zoest N. Gaaloul Y. Singh H. Ahlers W. Herr S. T. Seidel W. Ertmer E. Rasel M. Eckart E. Kajari S. Arnold G. Nandi W. P. Schleich R. Walser A. Vogel K. Sengstock K. Bongs W. Lewoczko-Adamczyk M. Schiemangk T. Schuldt T. Könemann H. Müntinga C. Lämmerzahl H. Dittus T. W. Hänsch J. Reichel article doi:10.1063/1.3537857 2010 10.1063/1.3537857 AIP Conference Proceedings 1323 283-295 1 E. Sadurní W. P. Schleich article doi:10.1080/09500340.2010.486873 2010 10.1080/09500340.2010.486873 Journal of Modern Optics 57 Taylor & Francis 1437-1444 14-15 R. Mack V. P. Yakovlev W. P. Schleich article VOGEL2010133 An appropriately prepared real-valued wave packet moving in one space dimension will focus during a brief period of time even in the absence of any force. We illustrate this phenomenon by considering the time evolution of the elementary superposition of the ground state and the second excited state of a harmonic oscillator. Moreover, we show that a variation of the superposition parameter leads us from a domain of enhanced spreading via a point of suppressed spreading to a region where the wave packets focuses before it spreads again. We determine the points of maximal spreading and optimal focusing. Our analysis of this unusual behavior of a free quantum particle rests on the time dependence of (i) the average separation of the wave packet from the origin, (ii) the probability density in position space, and (iii) the Wigner phase space distribution. We conclude our search for optimally focusing wave packets by solving the corresponding variational problem with respect to a family of measures expressing the width of the wave packet. 2010 0301-0104 https://doi.org/10.1016/j.chemphys.2010.07.002 Chemical Physics 375 133 - 143 2 Focusing wave packets, Wigner function http://www.sciencedirect.com/science/article/pii/S0301010410003137 Stochastic processes in Physics and Chemistry (in honor of Peter Hänggi) K. Vogel F. Gleisberg N. L. Harshman P. Kazemi R. Mack L. Plimak W. P. Schleich article SCHLEICH2010786 The familiar wave function for a free particle in two dimensions and in a state with definite values of energy and angular momentum shows some unusual effects. We identify the origin of these subtleties as interference in two-dimensional space where Huygens’ principle breaks down. Our arguments are based upon the corresponding Wigner function. 2010 0030-4018 https://doi.org/10.1016/j.optcom.2009.10.055 Optics Communications 283 786 - 789 5 http://www.sciencedirect.com/science/article/pii/S0030401809010475 Quo vadis Quantum Optics? W. P. Schleich J. P. Dahl S. Varro article Feiler2009 In the present paper we follow three major themes: (i) concepts of rotation in general relativity, (ii) effects induced by these generalized rotations, and (iii) their measurement using interferometry. Our journey takes us from the Foucault pendulum via the Sagnac interferometer to manifestations of gravito-magnetism in double binary pulsars and in G{"o}del's Universe. Throughout our article we emphasize the emerging role of matter wave interferometry based on cold atoms or Bose--Einstein condensates leading to superior inertial sensors. In particular, we advertise recent activities directed towards the operation of a coherent matter wave interferometer in an extended free fall. 2009 12 01 1572-9672 10.1007/s11214-009-9613-7 Space Science Reviews 148 123--147 1 https://doi.org/10.1007/s11214-009-9613-7 C. Feiler M. Buser E. Kajari W. P. Schleich E. M. Rasel R. F. O'Connell article PhysRevD.80.103002 2009 11 10.1103/PhysRevD.80.103002 Phys. Rev. D 80 American Physical Society 103002 https://link.aps.org/doi/10.1103/PhysRevD.80.103002 F. Grave M. Buser T. Müller G. Wunner W. P. Schleich article PhysRevB.80.134515 2009 10 10.1103/PhysRevB.80.134515 Phys. Rev. B 80 American Physical Society 134515 https://link.aps.org/doi/10.1103/PhysRevB.80.134515 K. Vogel W. P. Schleich T. Kato D. Koelle R. Kleiner E. Goldobin article PhysRevA.80.033624 2009 9 10.1103/PhysRevA.80.033624 Phys. Rev. A 80 American Physical Society 033624 https://link.aps.org/doi/10.1103/PhysRevA.80.033624 B. Berg L. I. Plimak A. Polkovnikov M. K. Olsen M. Fleischhauer W. P. Schleich article PhysRevA.80.022714 2009 8 10.1103/PhysRevA.80.022714 Phys. Rev. A 80 American Physical Society 022714 https://link.aps.org/doi/10.1103/PhysRevA.80.022714 M. A. Efremov L. Plimak B. Berg M. Yu. Ivanov W. P. Schleich article Ertmer2009 In response to ESA's Call for proposals of 5 March 2007 of the COSMIC VISION 2015--2025 plan of the ESA science programme, we propose a M-class satellite mission to test of the Equivalence Principle in the quantum domain by investigating the extended free fall of matter waves instead of macroscopic bodies as in the case of GAUGE, MICROSCOPE or STEP. The satellite, called Matter Wave Explorer of Gravity, will carry an experiment to test gravity, namely the measurement of the equal rate of free fall with various isotopes of distinct atomic species with precision cold atom interferometry in the vicinity of the earth. This will allow for a first quantum test the Equivalence Principle with spin polarised particles and with pure fermionic and bosonic atomic ensembles. Due to the space conditions, the free fall of Rubidium and Potassium isotopes will be compared with a maximum accelerational sensitivity of 5{\textperiodcentered}10{\thinspace}−{\thinspace}16 m/s2 corresponding to an accuracy of the test of the Equivalence Principle of 1 part in 1016. Besides the primary scientific goal, the quantum test of the Equivalence Principle, the mission can be extended to provide additional information about the gravitational field of the earth or for testing theories of fundamental processes of decoherence which are investigated by various theory groups in the context of quantum gravity phenomenology. In this proposal we present in detail the mission objectives and the technical aspects of the proposed mission. 2009 3 01 1572-9508 10.1007/s10686-008-9125-6 Experimental Astronomy 23 611--649 2 https://doi.org/10.1007/s10686-008-9125-6 W. Ertmer C. Schubert T. Wendrich M. Gilowski M. Zaiser T. v. Zoest E. Rasel Ch. J. Bordé A. Clairon P. Laurent P. Lemonde G. Santarelli W. Schleich F. S. Cataliotti M. Inguscio N. Poli F. Sorrentino C. Modugno G. M. Tino P. Gill H. Klein H. Margolis S. Reynaud C. Salomon A. Lambrecht E. Peik C. Jentsch U. Johann A. Rathke P. Bouyer L. Cacciapuoti P. De Natale B. Christophe B. Foulon P. Touboul L. Maleki N. Yu S. G. Turyshev J. D. Anderson R. Walser J. Vigué M. Büchner M.-C. Angonin P. Delva P. Tourrenc R. Bingham B. Kent A. Wicht L. J. Wang K. Bongs Hj. Dittus C. Lämmerzahl S. Theil K. Sengstock T. Müller M. Arndt L. Iess F. Bondu A. Brillet E. Samain M. L. Chiofalo F. Levi D. Calonico article PhysRevA.79.024101 2009 2 10.1103/PhysRevA.79.024101 Phys. Rev. A 79 American Physical Society 024101 https://link.aps.org/doi/10.1103/PhysRevA.79.024101 J. P. Dahl W. P. Schleich article Eckart_2009 We examine ground state correlations for repulsive, quasi one-dimensional bosons in a harmonic trap. In particular, we focus on the few particle limit N=2, 3, 4, …, where exact numerical solutions of the many particle Schrödinger equation are available, by employing the multi-configuration time-dependent Hartree method. Our numerical results for the inhomogeneous system are modeled with the analytical solution of the homogeneous problem using the Bethe ansatz and the local density approximation. Tuning the interaction strength from the weakly correlated Gross–Pitaevskii to the strongly correlated Tonks–Girardeau regime reveals finite particle number effects in the second-order correlation function beyond the local density approximation. 2009 2 10.1088/1367-2630/11/2/023010 New Journal of Physics 11 {IOP} Publishing 023010 2 https://doi.org/10.1088%2F1367-2630%2F11%2F2%2F023010 M. Eckart R. Walser W. P. Schleich S. Zöllner P. Schmelcher inbook 2009 Mathematical Analysis of Evolution, Information, and Complexity Wiley VCH

Weinheim

W. Arendt and W. Schleich 395-431 R. Mack W. P. Schleich D. Haase H. Maier article doi:10.1080/09500340903194625 2009 10.1080/09500340903194625 Journal of Modern Optics 56 Taylor & Francis 2118-2124 18-19 S. Wölk C. Feiler W. P. Schleich inproceedings 2009 Atom Optics and Space Physics Proceedings of the International School of Physics "Enrico Fermi" IOS Press

Amsterdam, Oxford, Tokyo, Washington DC

E. Arimondo, W. Ertmer, E. M. Rasel, and W. P. Schleich IX-XI E. Arimondo W. Ertmer E. M. Rasel W. P. Schleich inproceedings 2009 Atom Optics and Space Physics Proceedings of the International School of Physics "Enrico Fermi" IOS Press

Amsterdam, Oxford, Tokyo, Washington DC

E. Arimondo, W. Ertmer, E.M. Rasel and W.P. Schleich XXIII-XVI E. Arimondo W. Ertmer E. M. Rasel W. P. Schleich inbook 2009 Mathematical Analysis of Evolution, Information, and Complexity Wiley VCH

Weinheim

W. Arendt and W. Schleich XXIII-XXIX W. Arendt D. Mugnolo W. P. Schleich inproceedings 2009 Atom Optics and Space Physics Proceedings of the International School of Physics "Enrico Fermi" IOS Press

Amsterdam, Oxford, Tokyo, Washington DC

E. Arimondo, W. Ertmer, E. M. Rasel, and W. P. Schleich 45-148 E. Kajari M. Buser C. Feiler W. P. Schleich article 2009 Physik Journal 8 53 W. P. Schleich article _tefa_k_2008 We generalize the concept of factorization using truncated Gauss sums to exponential sums where the phase increases with the jth power of the summation index. For such sums the number of terms needed to suppress ghost factors of N scales as . Unfortunately, this advantageous scaling law is accompanied by a disadvantage: the gap between factors and non-factors decreases rapidly with increasing power j and as a consequence it gets more difficult to identify factors. This feature serves as our motivation to study sums with an exponential phase. Our numerical simulations indicate that in this case the scaling law is logarithmic and that we retain a significant gap between factors and non-factors. 2008 7 10.1088/1751-8113/41/30/304024 Journal of Physics A: Mathematical and Theoretical 41 {IOP} Publishing 304024 30 https://doi.org/10.1088%2F1751-8113%2F41%2F30%2F304024 M. Štefaňák D. Haase W. Merkel M. S. Zubairy W. P. Schleich article Eckart_2008 Phase correlations, density fluctuations and three-body loss rates are relevant for many experiments in quasi one-dimensional geometries. Extended mean-field theory is used to evaluate correlation functions up to third order for a quasi one-dimensional trapped Bose gas at zero and finite temperature. At zero temperature and in the homogeneous limit, we also study the transition from the weakly correlated Gross–Pitaevskii regime to the strongly correlated Tonks–Girardeau regime analytically. We compare our results with the exact Lieb–Liniger solution for the homogeneous case and find good agreement up to the cross-over regime. 2008 4 10.1088/1367-2630/10/4/045024 New Journal of Physics 10 {IOP} Publishing 045024 4 https://doi.org/10.1088%2F1367-2630%2F10%2F4%2F045024 M. Eckart R. Walser W. P. Schleich article Walser_2008 Josephson junctions (JJs) and junction arrays are well-studied devices in superconductivity. With external magnetic fields one can modulate the phase in a long junction and create traveling, solitonic waves of magnetic flux, called fluxons. Today, it is also possible to devise two different types of junctions: depending on the sign of the critical current density , they are called 0- or π-junctions. In turn, a 0–π junction is formed by joining two of these junctions. As a result, one obtains a pinned Josephson vortex of fractional magnetic flux, at the 0–π boundary. Here, we analyze this arrangement of superconducting junctions in the context of an atomic bosonic quantum gas, where two-state atoms in a double well trap are coupled in an analogous fashion. There, an all-optical 0–π JJ is created by the phase of a complex valued Rabi frequency and we derive a discrete four-mode model for this situation, which qualitatively resembles a semifluxon. 2008 4 10.1088/1367-2630/10/4/045020 New Journal of Physics 10 {IOP} Publishing 045020 4 https://doi.org/10.1088%2F1367-2630%2F10%2F4%2F045020 R. Walser E. Goldobin O. Crasser D. Koelle R. Kleiner W. P. Schleich article PhysRevLett.100.030202 2008 1 10.1103/PhysRevLett.100.030202 Phys. Rev. Lett. 100 American Physical Society 030202 https://link.aps.org/doi/10.1103/PhysRevLett.100.030202 D. Bigourd B. Chatel W. P. Schleich B. Girard article 2008 Themenheft Forschung Quantenmaterie 5 Universität Stuttgart 22-31 E. Goldobin R. Kleiner D. Kölle W. P. Schleich K. Vogel R. Walser article PhysRevLett.100.030201 2008 1 10.1103/PhysRevLett.100.030201 Phys. Rev. Lett. 100 American Physical Society 030201 https://link.aps.org/doi/10.1103/PhysRevLett.100.030201 M. Gilowski T. Wendrich T. Müller Ch. Jentsch W. Ertmer E. M. Rasel W. P. Schleich article 2008 Physik Journal 7 127 W. P. Schleich inproceedings 2008 Contemporary Physics: Proceedings of the International Symposium , National Centre for Physics Islamabad, Pakistan 26-30 March 2007 World Scientific

Singapore

J. Aslam, F. Hussain and Riazuddin 87-94 M. Štefaňák W. Merkel M. Mehring W. P. Schleich incollection 2008 Publikationsverhalten in unterschiedlichen Disziplinen, Beiträge zur Beurteilung von Forschungsleistungen 12 Diskussionspapiere der Alexander von Humboldt-Stiftung W. P. Schleich article doi:10.1002/prop.200810535 Abstract We analyze the structures emerging in the spacetime representation of the probability density woven by a slightly relativistic particle caught in a one-dimensional box. In particular, we evaluate the relativistic effects on the revival time and the specific changes produced in the intermode traces, which quantum carpets consist of. Moreover, we present a detailed mathematical analysis of such quantum carpets pursuing the approach of a kernel. Here we represent the probability distribution as a superposition of interfering Airy function-type structures along straight world lines. We also show that this phenomenon can be enhanced by many orders of magnitude in semiconductors with narrow band-gap (e.g. as in InSb) and small effective mass of the electron, whereby due to the strong nonparabolicity of the semiconductor conduction band, the electron energy vs momentum dispersion relation behaves in a pseudo-relativistic way. 2008 10.1002/prop.200810535 Fortschritte der Physik 56 967-992 10 wave packets, one-dimensional box, Talbot effect, Green function https://onlinelibrary.wiley.com/doi/abs/10.1002/prop.200810535 I. Marzoli A. E. Kaplan F. Saif W. P. Schleich article 2008 Physik Journal 7 126 H. Pfister W. P. Schleich article Koenemann2007 We experimentally demonstrate the possibility of preparing ultracold atoms in the environment of weightlessness at the earth-bound short-term microgravity laboratory Drop Tower Bremen, a facility of ZARM -- University of Bremen. Our approach is based on a freely falling magneto-optical trap (MOT) drop tower experiment performed within the ATKAT collaboration (``Atom-Catapult'') as a preliminary part of the QUANTUS pilot project (``Quantum Systems in Weightlessness'') pursuing a Bose--Einstein condensate (BEC) in microgravity at the drop tower [1, 2]. 2007 12 01 1432-0649 10.1007/s00340-007-2863-8 Applied Physics B 89 431--438 4 https://doi.org/10.1007/s00340-007-2863-8 T. Könemann W. Brinkmann E. Göklü C. Lämmerzahl H. Dittus T. Zoest E. M. Rasel W. Ertmer W. Lewoczko-Adamczyk M. Schiemangk A. Vogel G. Johannsen S. Wildfang K. Bongs K. Sengstock E. Kajari G. Nandi R. Walser W. P. Schleich article PhysRevA.76.063617 2007 12 10.1103/PhysRevA.76.063617 Phys. Rev. A 76 American Physical Society 063617 https://link.aps.org/doi/10.1103/PhysRevA.76.063617 G. Nandi R. Walser E. Kajari W. P. Schleich article _tefa_k_2007 Recent experiments have shown that truncated Gauss sums allow us to find the factors of an integer N. This method relies on the fact that for a factor the absolute value of the Gauss sum is unity. However, for every integer N there exist integers which are not factors, but where the Gauss sum reaches a value which is arbitrarily close to unity. In order to distinguish such ghost factors from real factors we need to amplify this difference. We show that a proper choice of the truncation parameter of the Gauss sum suppresses the ghost factors below a threshold value. We derive the scaling law of the truncation parameter on the number to be factored. Moreover, we show that this scaling law is also necessary for the success of our factorization scheme, even if we relax the threshold or allow limited error tolerance. 2007 10 10.1088/1367-2630/9/10/370 New Journal of Physics 9 {IOP} Publishing 370--370 10 https://doi.org/10.1088%2F1367-2630%2F9%2F10%2F370 M. Štefaňák W. Merkel W. P. Schleich D. Haase H. Maier article PhysRevA.76.023417 2007 8 10.1103/PhysRevA.76.023417 Phys. Rev. A 76 American Physical Society 023417 https://link.aps.org/doi/10.1103/PhysRevA.76.023417 W. Merkel H. Mack W. P. Schleich G. G. Paulus B. Girard article Grupp_2007 We consider Feshbach scattering of fermions in a one-dimensional optical lattice. By formulating the scattering theory in the crystal momentum basis, one can exploit the lattice symmetry and factorize the scattering problem in terms of centre-of-mass and relative momentum in the reduced Brillouin zone scheme. Within a single-band approximation, we can tune the position of a Feshbach resonance with the centre-of-mass momentum due to the non-parabolic form of the energy band. 2007 6 10.1088/0953-4075/40/13/014 Journal of Physics B: Atomic, Molecular and Optical Physics 40 {IOP} Publishing 2703--2718 13 https://doi.org/10.1088%2F0953-4075%2F40%2F13%2F014 M. Grupp R. Walser W. P. Schleich A. Muramatsu M. Weitz article PhysRevA.75.052107 2007 5 10.1103/PhysRevA.75.052107 Phys. Rev. A 75 American Physical Society 052107 https://link.aps.org/doi/10.1103/PhysRevA.75.052107 J. P. Dahl S. Varro A. Wolf W. P. Schleich article PhysRevA.75.033420 2007 3 10.1103/PhysRevA.75.033420 Phys. Rev. A 75 American Physical Society 033420 https://link.aps.org/doi/10.1103/PhysRevA.75.033420 W. Merkel H. Mack M. Freyberger V. V. Kozlov W. P. Schleich B. W. Shore article PhysRevLett.98.120502 2007 3 10.1103/PhysRevLett.98.120502 Phys. Rev. Lett. 98 American Physical Society 120502 https://link.aps.org/doi/10.1103/PhysRevLett.98.120502 M. Mehring K. Müller I. Sh. Averbukh W. Merkel W. P. Schleich article TINO2007159 We present projects for future space missions using new quantum devices based on ultracold atoms. They will enable fundamental physics experiments testing quantum physics, physics beyond the standard model of fundamental particles and interactions, special relativity, gravitation and general relativity. 2007 0920-5632 https://doi.org/10.1016/j.nuclphysbps.2006.12.061 Nuclear Physics B - Proceedings Supplements 166 159 - 165 http://www.sciencedirect.com/science/article/pii/S0920563206010152 Proceedings of the Third International Conference on Particle and Fundamental Physics in Space G. M. Tino L. Cacciapuoti K. Bongs Ch. J. Bordé P. Bouyer H. Dittus W. Ertmer A. Görlitz M. Inguscio A. Landragin P. Lemonde C. Lämmerzahl E. Rasel J. Reichel C. Salomon S. Schiller W. Schleich K. Sengstock U. Sterr M. Wilkens article doi:10.1142/S0218271807011358 In this article we present actual projects concerning high resolution measurements developed for future space missions based on ultracold atoms at the Institut für Quantenoptik (IQ) of the University of Hannover. This work involves the realization of a Bose–Einstein condensate in a microgravitational environment and of an inertial atomic quantum sensor. 2007 10.1142/S0218271807011358 International Journal of Modern Physics D 16 2421-2429 12b T. van Zoest T. Müller T. Wendrich M. Gilowski E. M. Rasel W. Ertmer T. Könemann C. Lämmerzahl H. J. Dittus A. Vogel K. Bongs K. Sengstock W. Lewoczko J. Reichel G. Nandi W. Schleich R. Walser inproceedings 2007 10.1117/12.704287 Complex Light and Optical Forces Proc. SPIE 6483 T. van Zoest T. Müller T. Wendrich M. Gilowski E. M. Rasel T. Könemann C. Lämmerzahl H. J. Dittus A. Vogel K. Bongs K. Sengstock W. Lewoczko J. Reichel G. Nandi W. Schleich R. Walser W. Ertmer inbook 2007 Elements of Quantum Information Wiley-VCH

Weinheim

W. P. Schleich and H. Walther 339-353 W. Merkel I. Sh. Averbukh B. Girard M. Mehring G. G. Paulus W. P. Schleich article doi:10.1080/09500340600736843 2007 10.1080/09500340600736843 Journal of Modern Optics 54 Taylor & Francis 1595-1606 11 S. Zippilli G. Morigi W. P. Schleich article doi:10.1080/09500340701621266 2007 10.1080/09500340701621266 Journal of Modern Optics 54 Taylor & Francis 2513-2522 16-17 K. Bongs W. Brinkmann H. Dittus W. Ertmer E. Göklü G. Johannsen E. Kajari T. Könemann C. Lämmerzahl W. Lewoczko-Adamczyk G. Nandi E. M. Rasel W. P. Schleich M. Schiemangk K. Sengstock A. Vogel R. Walser S. Wildfang article doi:10.1142/S0218271807011620 Weightlessness promises to substantially extend the science of quantum gases toward presently inaccessible regimes of low temperatures, macroscopic dimensions of coherent matter waves, and enhanced duration of unperturbed evolution. With the long-term goal of studying cold quantum gases on a space platform, we currently focus on the implementation of an 87Rb Bose–Einstein condensate (BEC) experiment under microgravity conditions at the ZARM drop tower in Bremen (Germany). Special challenges in the construction of the experimental setup are posed by a low volume of the drop capsule (< 1 m3) as well as critical vibrations during capsule release and peak decelerations of up to 50 g during recapture at the bottom of the tower. All mechanical and electronic components have thus been designed with stringent demands on miniaturization, mechanical stability and reliability. Additionally, the system provides extensive remote control capabilities as it is not manually accessible in the tower two hours before and during the drop. We present the robust system and show results from first tests at the drop tower. 2007 10.1142/S0218271807011620 International Journal of Modern Physics D 16 2447-2454 12b W. Lewoczko-Adamczyk T. van Zoest E. M. Rasel W. Ertmer A. Vogel S. Wildfang G. Johannsen K. Bongs K. Sengstock J. Reichel T. Könemann W. Brinkmann C. Lämmerzahl H. J. Dittus G. Nandi W. Schleich R. Walser article 2007 Laser Physics 17 903-907 P. Cañzares T. Görler J. P. Paz G. Morigi W. P. Schleich article doi:10.1080/09500340701336535 2007 10.1080/09500340701336535 Journal of Modern Optics 54 Taylor & Francis 2017-2032 13-15 J. P. Dahl S. Varro A. Wolf W. P. Schleich article PhysRevA.74.042323 2006 10 10.1103/PhysRevA.74.042323 Phys. Rev. A 74 American Physical Society 042323 https://link.aps.org/doi/10.1103/PhysRevA.74.042323 J. P. Dahl H. Mack A. Wolf W. P. Schleich article Vogel2006 We report the current status of our cooperative effort to realize a 87Rb Bose--Einstein condensate in microgravity. Targeting the long-term goal of studying cold quantum gases on a space platform, we currently focus on the implementation of an experiment at the ZARM drop tower in Bremen. Fulfilling the technical requirements for operation in this facility, the complete experimental setup will fit in a volume of less than 1 m3 with a total mass below 150 kg and a total power consumption of the order of 625 W. The individual parts of the setup, in particular the ultra-compact laser system as a critical component, are presented. In addition, we discuss a first demonstration of the mechanical and frequency control stability of the laser modules. On the theoretical side, we outline the non-relativistic description of a freely falling many-particle system in the rotating frame of the Earth. In particular, we show that the time evolution of a harmonically trapped, collisionally interacting degenerate gas of bosons or fermions is as simple in an accelerated, rotating frame of reference as in an inertial frame. By adopting a co-moving generalized Galilean frame, we can eliminate inertial forces and torques. This leads to important simplifications for numerical simulation of the experiment. 2006 9 01 1432-0649 10.1007/s00340-006-2359-y Applied Physics B 84 663--671 4 https://doi.org/10.1007/s00340-006-2359-y A. Vogel M. Schmidt K. Sengstock K. Bongs W. Lewoczko T. Schuldt T. van Zoest W. Ertmer E. Rasel J. Reichel T. Könemann W. Brinkmann E. Göklü C. Lämmerzahl H. J. Dittus G. Nandi W. P. Schleich R. Walser article PhysRevA.73.050701 2006 5 10.1103/PhysRevA.73.050701 Phys. Rev. A 73 American Physical Society 050701 https://link.aps.org/doi/10.1103/PhysRevA.73.050701 M. Grupp G. Nandi R. Walser W. P. Schleich article doi:10.1142/S021797920603439X We present two physical systems which make Gauß sums experimentally accessible. The probability amplitude for a two-photon transition in an appropriate ladder system driven by a chirped laser pulse is determined by a Gauß sum. The autocorrelation function of a quantum rotor is also of the form of a Gauß sum. These examples suggest rules for determining prime factor components on the basis of the properties of Gauß sums. Moreover, we show how Gauß sums are related to the Riemann Zeta function. 2006 10.1142/S021797920603439X International Journal of Modern Physics B 20 1893-1916 11n13 W. Merkel O. Crasser F. Haug H. Mack M. Freyberger W. P. Schleich I. Averbukh M. Bienert B. Girard H. Maier G. G. Paulus article doi:10.1002/lapl.200510055 Abstract The results on non-spreading Michelangelo wave packets [7, 8] are generalized to the case of a semi-open two-level system when some fraction of atoms falls back to the lower state due to spontaneous transitions. The proposed approach is based on the solution of the Generalized Optical Bloch Equations for the atomic density matrix. The spatial features of arising nonspreading wave packets as well as the atomic momentum distribution are compared with the case of an open two-level system. (© 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH \& Co. KGaA) 2006 10.1002/lapl.200510055 Laser Physics Letters 3 31-36 1 atom optics, wave packets, lithography https://onlinelibrary.wiley.com/doi/abs/10.1002/lapl.200510055 S. V. Petropavlovsky V. P. Yakovlev M. A. Efremov M. V. Fedorov W. P. Schleich article doi:10.1002/prop.200610315 Abstract The periodicity properties of Gauss sums allow us to factor integer numbers. We show that the excitation probability amplitudes of appropriate quantum systems interacting with specific laser fields are determined by Gauss sums. The resulting probabilities are experimentally accessible by measuring the fluorescence from this level. In particular, we discuss a two-photon transition in a ladder system driven by a chirped laser pulse. In addition, we consider two realizations of laser driven one-photon transitions. For each quantum system we demonstrate the power of this factorization scheme using numerical examples. 2006 10.1002/prop.200610315 Fortschritte der Physik 54 856-865 8‐10 Gauss sums, chirped pulses, factorization of numbers https://onlinelibrary.wiley.com/doi/abs/10.1002/prop.200610315 W. Merkel I. Sh. Averbukh B. Girard G. G. Paulus W. P. Schleich inbook Freyberger2006 The electromagnetic field appears almost everywhere in physics. Following the introduction of Maxwell's equations in 1864, Max Planck initiated quantum theory when he discovered h{\thinspace}={\thinspace}2$\pi$ℏ in the laws of black-body radiation. In 1905 Albert Einstein explained the photoelectric effect on the hypothesis of a corpuscular nature of radiation and in 1917 this paradigm led to a description of the interaction between atoms and electromagnetic radiation. 2006 978-0-387-26308-3 10.1007/978-0-387-26308-3_78 Springer

New York, NY

G. Drake 1141--1165 https://doi.org/10.1007/978-0-387-26308-3_78 M. Freyberger K. Vogel W. Schleich R. O'Connell article PLIMAK2006311 We analyse and numerically simulate the full many-body quantum dynamics of a spin-1 condensate in the single spatial mode approximation. Initially, the condensate is in a “ferromagnetic” state with all spins aligned along the y axis and the magnetic field pointing along the z axis. In the course of evolution the spinor condensate undergoes a characteristic change of symmetry, which in a real experiment could be a signature of spin-mixing many-body interactions. The results of our simulations are conveniently visualised within the picture of irreducible tensor operators. 2006 0030-4018 https://doi.org/10.1016/j.optcom.2006.03.074 Optics Communications 264 311 - 320 2 Cold atoms, Trapped atoms, Bose condensate, Spinor condensate, Nonequilibrium dynamics, Many Body Theory http://www.sciencedirect.com/science/article/pii/S0030401806004913 Quantum Control of Light and Matter L. I. Plimak C. Weiß R. Walser W. P. Schleich inbook 2006 10.1007/978-3-540-47008-3_2 Laser Physics and Application VIII/1A2 Springer

Berlin, Heidelberg

Laser Fundamentals, Landolt-Börnstein H. Weber, G. Herziger and R. Poprawe 3-46 https://materials.springer.com/lb/docs/sm_lbs_978-3-540-47008-3_2 F. Haug M. Freyberger K. Vogel W. P. Schleich article PhysRevLett.95.110405 2005 9 10.1103/PhysRevLett.95.110405 Phys. Rev. Lett. 95 American Physical Society 110405 https://link.aps.org/doi/10.1103/PhysRevLett.95.110405 R. Stützle M. C. Göbel Th. Hörner E. Kierig I. Mourachko M. K. Oberthaler M. A. Efremov M. V. Fedorov V. P. Yakovlev K. A. H. van Leeuwen W. P. Schleich article Efremov_2005 The formation of two-dimensional nonspreading atomic wave packets produced in the interaction of a beam of two-level atoms with two standing light waves polarised in the same plane is considered. The mechanism providing a dispersionless particle dynamics is the balance of two processes: a rapid decay of the atomic wave function away from the field nodes due to spontaneous transitions to nonresonance states and the quantum broadening of the wave packets formed in the close vicinity of field nodes. Coordinate-dependent amplitudes and phases of the two-dimensional wave packets were found for the jg=0 ↔ je=1 transition. 2005 8 10.1070/qe2005v035n08abeh009145 Quantum Electronics 35 {IOP} Publishing 675--678 8 https://doi.org/10.1070%2Fqe2005v035n08abeh009145 M. A. Efremov S. V. Petropavlovsky M. V. Fedorov W. P. Schleich V. P. Yakovlev article PhysRevB.72.054527 2005 8 10.1103/PhysRevB.72.054527 Phys. Rev. B 72 American Physical Society 054527 https://link.aps.org/doi/10.1103/PhysRevB.72.054527 E. Goldobin K. Vogel O. Crasser R. Walser W. P. Schleich D. Koelle R. Kleiner article PhysRevA.71.053601 2005 5 10.1103/PhysRevA.71.053601 Phys. Rev. A 71 American Physical Society 053601 https://link.aps.org/doi/10.1103/PhysRevA.71.053601 B. Mohring M. Bienert F. Haug G. Morigi W. P. Schleich M. G. Raizen article PhysRevA.71.043803 2005 4 10.1103/PhysRevA.71.043803 Phys. Rev. A 71 American Physical Society 043803 https://link.aps.org/doi/10.1103/PhysRevA.71.043803 F. Haug M. Bienert W. P. Schleich T. H. Seligman M. G. Raizen article 2005 Laser Physics 15 18-36 J. P. Dahl D. M. Greenberger M. J. W. Hall G. Süßmann A. Wolf W. P. Schleich article 2005 Physik Journal 4 22-23 W. P. Schleich article 2005 Physik Journal 4 21-26 W. P. Schleich H. Walther article Kajari2004 We present exact expressions for the Sagnac effect of G{"o}del's Universe. For this purpose we first derive a formula for the Sagnac time delay along a circular path in the presence of an arbitrary stationary metric in cylindrical coordinates. We then apply this result to G{"o}del's metric for two different experimental situations: First, the light source and the detector are at rest relative to the matter generating the gravitational field. In this case we find an expression that is formally equivalent to the familiar nonrelativistic Sagnac time delay. Second, the light source and the detector are rotating relative to the matter. Here we show that for a special rotation rate of the detector the Sagnac time delay vanishes. Finally we propose a formulation of the Sagnac time delay in terms of invariant physical quantities. We show that this result is very close to the analogous formula of the Sagnac time delay of a rotating coordinate system in Minkowski spacetime. 2004 10 01 1572-9532 10.1023/B:GERG.0000046184.03333.9f General Relativity and Gravitation 36 2289--2316 10 https://doi.org/10.1023/B:GERG.0000046184.03333.9f E. Kajari R. Walser W. P. Schleich A. Delgado article PhysRevA.69.063606 2004 6 10.1103/PhysRevA.69.063606 Phys. Rev. A 69 American Physical Society 063606 https://link.aps.org/doi/10.1103/PhysRevA.69.063606 G. Nandi R. Walser W. P. Schleich article Mazets_2004 We study a gaseous atomic Bose–Einstein condensate with laser-induced dipole–dipole interactions using the Hartree–Fock–Bogoliubov theory within the Popov approximation. The dipolar interactions introduce long-range atom–atom correlations which manifest themselves as increased depletion at momenta similar to that of the laser wavelength, as well as a ‘roton’ dip in the excitation spectrum. Surprisingly, the roton dip and the corresponding peak in the depletion are enhanced by raising the temperature above absolute zero. 2004 3 10.1088/0953-4075/37/7/061 Journal of Physics B: Atomic, Molecular and Optical Physics 37 {IOP} Publishing S155--S164 7 https://doi.org/10.1088%2F0953-4075%2F37%2F7%2F061 I. E. Mazets D. H. J. O'Dell G. Kurizki N. Davidson W. P. Schleich article doi:10.1142/S0217979204024550 We present a brief review of our recent results concerning non-mean-field effects of laser-induced dipole–dipole interactions on static and dynamical properties of atomic Bose–Einstein condensates. 2004 10.1142/S0217979204024550 International Journal of Modern Physics B 18 961-974 07 G. Kurizki I. E. Mazets D. H. J. O'Dell W. P. Schleich article doi:10.1142/S021947750400163X We formulate and argue in favor of the following conjecture: There exists an intimate connection between Wigner's quantum mechanical phase space distribution function and classical Fresnel optics. 2004 10.1142/S021947750400163X Fluctuation and Noise Letters 04 L43-L51 01 O. Crasser H. Mack W. P. Schleich inbook 2004 Die 10 schönsten Physikexperimente aller Zeiten Rowohlt-Taschenbuchverlag

Reinbek

W. P. Schleich article doi:10.1002/prop.200410182 We compare and contrast classical and quantum dynamics of a free particle initially prepared in an s-wave. Due to the wave nature of quantum theory the particle experiences an acceleration which depends on the number of space dimensions. 2004 10.1002/prop.200410182 Fortschritte der Physik 52 1118-1133 11‐12 https://onlinelibrary.wiley.com/doi/abs/10.1002/prop.200410182 J. P. Dahl A. Wolf W. P. Schleich inbook 2004 Bergmann-Schäfer, Lehrbuch der Experimentalphysik 3: Optik Walther de Gruyter

Berlin

7 H. Niedrig M. Freyberger F. Haug W. P. Schleich K. Vogel article doi:10.1021/jp049616r 2004 10.1021/jp049616r The Journal of Physical Chemistry A 108 8713-8720 41 J. P. Dahl W. P. Schleich article Fedorov2003 The scattering of atoms by a resonance standing light wave is considered under conditions when the lower of two resonance levels is metastable, while the upper level rapidly decays due to mainly spontaneous radiative transitions to the nonresonance levels of an atom. The diffraction scattering regime is studied, when the Rabi frequency is sufficiently high and many diffraction maxima are formed due to scattering. The dynamics of spontaneous radiation of an atom is investigated. It is shown that scattering slows down substantially the radiative decay of the atom. The regions and characteristics of the power and exponential decay are determined. The adiabatic and nonadiabatic scattering regimes are studied. It is shown that the wave packets of atoms in the metastable and resonance excited states narrow down during scattering. A limiting (minimal) size of the wave packets is found, which is achieved upon nonadiabatic scattering in the case of a sufficiently long interaction time. 2003 9 01 1090-6509 10.1134/1.1618338 Journal of Experimental and Theoretical Physics 97 522--538 3 https://doi.org/10.1134/1.1618338 M. V. Fedorov M. A. Efremov V. P. Yakovlev W. P. Schleich article PhysRevLett.91.010401 2003 6 10.1103/PhysRevLett.91.010401 Phys. Rev. Lett. 91 American Physical Society 010401 https://link.aps.org/doi/10.1103/PhysRevLett.91.010401 P. Lougovski E. Solano Z. M. Zhang H. Walther H. Mack W. P. Schleich article Botero2003 We express the commutation relation between the operators of the momentum and the radial unit vectors in D dimensions in differential and integral form. We connect this commutator with the quantum fictitious potential emerging in the radial Schr{"o}dinger equation of an s-wave. 2003 2 01 1432-0649 10.1007/s00340-003-1113-y Applied Physics B 76 129--133 2 https://doi.org/10.1007/s00340-003-1113-y J. Botero M. A. Cirone J. P. Dahl F. Straub W. P. Schleich article article 2003 10.1201/9781420044256.ch5 Optics and Photonics News 14 28-35 H. Mack W. P. Schleich article doi:10.1002/prop.200310007 Abstract It is an elementary aspect of the Weyl-Wigner representation of quantum mechanics that the dynamical phase-space function corresponding to the square of a quantum-mechanical operator is, in general, different from the square of the function representing the operator itself. We call attention to some conceptual consequences of this fact. 2003 10.1002/prop.200310007 Fortschritte der Physik 51 85-91 2‐3 https://onlinelibrary.wiley.com/doi/abs/10.1002/prop.200310007 J. P. Dahl W. P. Schleich article 2003 Laser Physics 13 995-1003 7 M. A. Efremov M. Fedorov V. P. Yakovlev W. P. Schleich inbook doi:10.1142/9789812704634_0039 We discuss the average kinetic energy of N non-interacting quantum particles in its dependence on N. For a peculiar entangled state, the kinetic energy increases quadratically with N, in contrast to its behavior in simple thermodynamics. 2003 10.1142/9789812704634_0039 The Physics of Communication Proceedings of XXII Solvay Conference on Physics World Scientific

Singapore

I. Antoniou, V. A. Sadovnichy and H. Walther 568-575 J. Botero M. A. Cirone J. P. Dahl A. Delgado W. P. Schleich article doi:10.1002/prop.200310065 Abstract We develop the Wigner phase space representation of a kicked particle for an arbitrary but periodic kicking potential. We use this formalism to illustrate quantum resonances and anti-resonances. 2003 10.1002/prop.200310065 Fortschritte der Physik 51 474-486 4‐5 https://onlinelibrary.wiley.com/doi/abs/10.1002/prop.200310065 M. Bienert F. Haug W. P. Schleich M. G. Raizen article 2003 uni ulm intern, Das Ulmer Universitätsmagazin 261 25-27 W. P. Schleich article Bia_lslash_ynicki_Birula_2002 Two particles of identical mass attract and repel each other even when there exist no classical external forces and their average relative momentum vanishes. This quantum force depends crucially on the number of dimensions of space. 2002 8 10.1088/1464-4266/4/4/326 Journal of Optics B: Quantum and Semiclassical Optics 4 {IOP} Publishing S393--S396 4 https://doi.org/10.1088%2F1464-4266%2F4%2F4%2F326 I. Białynicki-Birula M. A. Cirone J. P. Dahl R. F. O'Connell W. P. Schleich article PhysRevLett.89.060404 2002 7 10.1103/PhysRevLett.89.060404 Phys. Rev. Lett. 89 American Physical Society 060404 https://link.aps.org/doi/10.1103/PhysRevLett.89.060404 I. Białynicki-Birula M. A. Cirone J. P. Dahl M. Fedorov W. P. Schleich article PhysRevLett.89.050403 2002 7 10.1103/PhysRevLett.89.050403 Phys. Rev. Lett. 89 American Physical Society 050403 https://link.aps.org/doi/10.1103/PhysRevLett.89.050403 M. Bienert F. Haug W. P. Schleich M. G. Raizen article Delgado_2002 Some exact solutions of Einstein's field equations represent a rotating universe. One example is Gödel's cosmological model. Bianchi solutions generalize the Gödel metric and include the expansion of the universe. We propose a measurement of the cosmic rotation using a light or matter wave interferometer based on the Sagnac effect. Entanglement between the quanta employed in this quantum gyroscope enhances the accuracy, thereby coming closer to the more-than-challenging requirements of such experiments. 2002 6 10.1088/1367-2630/4/1/337 New Journal of Physics 4 {IOP} Publishing 37--37 https://doi.org/10.1088%2F1367-2630%2F4%2F1%2F337 A. Delgado W. P. Schleich G. Süßmann article PhysRevA.65.052109 2002 4 10.1103/PhysRevA.65.052109 Phys. Rev. A 65 American Physical Society 052109 https://link.aps.org/doi/10.1103/PhysRevA.65.052109 W. P. Schleich J. P. Dahl article PhysRevA.65.052110 2002 4 10.1103/PhysRevA.65.052110 Phys. Rev. A 65 American Physical Society 052110 https://link.aps.org/doi/10.1103/PhysRevA.65.052110 P. Törmä I. Jex W. P. Schleich article Meneghini_2002 We study the dynamics of atomic waves in a two-dimensional light crystal formed by two crossed standing laser fields. The longitudinal modulation of the crystal with the Doppler frequency significantly influences the transversal spatial modulation of the atomic wave. Near the doppleron resonance the atomic density shows a fractional space period. In this case a normally incident wave gives rise to an almost perfect conversion into the first momentum components and the light crystal acts as a highly efficient beamsplitter. The crossing angle, determining the Doppler frequency, is the easy-to-control parameter of the system. 2002 4 10.1088/1464-4266/4/3/301 Journal of Optics B: Quantum and Semiclassical Optics 4 {IOP} Publishing 165--171 3 https://doi.org/10.1088%2F1464-4266%2F4%2F3%2F301 S. Meneghini I. Jex W. P. Schleich V. P. Yakovlev article KONDRASHIN2002319 We use anomalous kinetics to create a narrow non-zero atomic velocity distribution. Moreover, we propose a method to control the anomalous transport of atoms in an optical lattice using a polarization gradient. We derive the threshold for this behavior by two different methods. 2002 0301-0104 https://doi.org/10.1016/S0301-0104(02)00555-4 Chemical Physics 284 319 - 330 1 Anomalous transport, Lévi flights, Optical lattice http://www.sciencedirect.com/science/article/pii/S0301010402005554 Strange Kinetics M. P. Kondrashin S. Schaufler W. P. Schleich V. P. Yakovlev article PhysRevA.65.022109 2002 1 10.1103/PhysRevA.65.022109 Phys. Rev. A 65 American Physical Society 022109 https://link.aps.org/doi/10.1103/PhysRevA.65.022109 J. P. Dahl W. P. Schleich inbook Riedel2002 The phenomenon of localization manifests itself in many quantum mechanical systems ranging from the localization of light in a random medium via Anderson localization of an electronic wave to the motion of atoms in time-dependent laser fields. In all these cases the underlying classical system is chaotic and shows diffusion as a function of time. In contrast, the quantum mechanical counterpart has a localized wave function whose width is governed by the classical diffusion and Planck's constant. In this paper we show that there exists an additional quantum parameter that controls the localization length. In the system of a two-level ion stored in a Paul trap and interacting with a standing wave it is the detuning between the transition frequency and the laser field. We also discuss the effect of decoherence in form of spontaneous emission. 2002 978-0-306-47097-4 10.1007/0-306-47097-7_43 Springer US

Boston, MA

P. Kumar, G. M. D'Ariano and O. Hirota 321--330 https://doi.org/10.1007/0-306-47097-7_43 K. Riedel P. Törmä V. Savichev W. P. Schleich inbook 2002 Quantum Information Technology VCH-Wiley

Weinheim

G. Leuchs and Th. Beth Th. C. Bschorr D. G. Fischer H. Mack W. P. Schleich M. Freyberger article quantumfictious Abstract We present Heisenberg's equation of motion for the radial variable of a free non-relativistic particle in D dimensions. The resulting radial force consists of three contributions: (i) the quantum fictitious force which is either attractive or repulsive depending on the number of dimensions, (ii) a singular quantum force located at the origin, and (iii) the centrifugal force associated with non-vanishing angular momentum. Moreover, we use Heisenberg's uncertainty relation to introduce a lower bound for the kinetic energy of an ensemble of neutral particles. This bound is quadratic in the number of atoms and can be traced back to the repulsive quantum fictitious potential. All three forces arise for a free particle: “Force without force”. 2002 10.1002/1521-3978(200205)50:5/7<599::AID-PROP599>3.0.CO;2-G Fortschritte der Physik 50 599-607 5‐7 https://onlinelibrary.wiley.com/doi/abs/10.1002/1521-3978%28200205%2950%3A5/7%3C599%3A%3AAID-PROP599%3E3.0.CO%3B2-G I. Białynicki-Birula M. A. Cirone J. P. Dahl T. H. Seligman F. Straub W. P. Schleich inbook 2002 10.3254/978-1-61499-004-8-369 Experimental Quantum Computation and Information 148 IOS Press

Amsterdam, Oxford, Tokyo, Washington DC

Proceedings of the International School of Physics "Enrico Fermi" F. De Martini and C. Monroe 369-384 H. Mack M. Bienert F. Haug F. Straub M. Freyberger W. P. Schleich article wavepackets Abstract We draw attention to various aspects of number theory emerging in the time evolution of elementary quantum systems with quadratic phases. Such model systems can be realized in actual experiments. Our analysis paves the way to a new, promising and effective method to factorize numbers. 2002 10.1002/1521-3951(200210)233:3<408::AID-PSSB408>3.0.CO;2-N physica status solidi (b) 233 408-415 3 03.67.–a, 42.25.–p, 42.25.Hz https://onlinelibrary.wiley.com/doi/abs/10.1002/1521-3951%28200210%29233%3A3%3C408%3A%3AAID-PSSB408%3E3.0.CO%3B2-N H. Mack M. Bienert F. Haug M. Freyberger W. P. Schleich article Cirone_2001 Huygens' principle following from the d'Alembert wave equation is not valid in two-dimensional space. A Schrödinger particle of vanishing angular momentum moving freely in two dimensions experiences an attractive force - the quantum anti-centrifugal force - towards its centre. We connect these two phenomena by comparing and contrasting the radial propagators of the d'Alembert wave equation and of a free non-relativistic quantum mechanical particle in two and three dimensions. 2001 12 10.1088/0953-4075/35/1/314 Journal of Physics B: Atomic, Molecular and Optical Physics 35 {IOP} Publishing 191--203 1 https://doi.org/10.1088%2F0953-4075%2F35%2F1%2F314 M. A. Cirone J. P. Dahl M. Fedorov D. M. Greenberger W. P. Schleich article PhysRevA.65.022101 2001 12 10.1103/PhysRevA.65.022101 Phys. Rev. A 65 American Physical Society 022101 https://link.aps.org/doi/10.1103/PhysRevA.65.022101 M. A. Cirone K. Rza̧żewski W. P. Schleich F. Straub J. A. Wheeler article Gleisberg_2001 The Wigner function W(z,k) for a model of interacting one-dimensional fermions confined to a harmonic trap is evaluated at zero temperature. The model considers two hyperfine states of the same fermionic species and treats the dominant interactions between the two using the bosonization method. Interactions substantially modify the shape of the Wigner function. Irrespective of the sign of the coupling constant, the Friedel oscillations inherent in the Wigner function are enhanced in the k-direction and suppressed in the z-direction. 2001 11 10.1088/0953-4075/34/23/309 Journal of Physics B: Atomic, Molecular and Optical Physics 34 {IOP} Publishing 4645--4651 23 https://doi.org/10.1088%2F0953-4075%2F34%2F23%2F309 F. Gleisberg W. P. Schleich W. Wonneberger article Berry_2001 In 1836 Henry Fox Talbot, an inventor of photography, published the results of some experiments in optics that he had previously demonstrated at a British Association meeting in Bristol (figure 1a). “It was very curious to observe that though the grating was greatly out of the focus of the lens...the appearance of the bands was perfectly distinct and well defined...the experiments are communicated in the hope that they may prove interesting to the cultivators of optical science.” 2001 6 10.1088/2058-7058/14/6/30 Physics World 14 {IOP} Publishing 39--46 6 https://doi.org/10.1088%2F2058-7058%2F14%2F6%2F30 M. Berry I. Marzoli W. Schleich article PhysRevA.63.065601 2001 5 10.1103/PhysRevA.63.065601 Phys. Rev. A 63 American Physical Society 065601 https://link.aps.org/doi/10.1103/PhysRevA.63.065601 K. Burnett O. M. Friesch B. Kneer W. P. Schleich article PhysRevA.63.043613 2001 3 10.1103/PhysRevA.63.043613 Phys. Rev. A 63 American Physical Society 043613 https://link.aps.org/doi/10.1103/PhysRevA.63.043613 J. Ruostekoski B. Kneer W. P. Schleich G. Rempe article doi:10.1063/1.1369661 2001 10.1063/1.1369661 The Journal of Chemical Physics 114 9901-9910 22 Ch. Warmuth A. Tortschanoff F. Milota M. Leibscher M. Shapiro Y. Prior I. Sh. Averbukh W. Schleich W. Jakubetz H. F. Kauffmann article 2001 10.1515/zna-2001-0109 Zeitschrift für Naturforschung A 56 48-60 1-2 M. A. Cirone G. Metikas W. P. Schleich article Saif_2000 Quantum revivals are investigated for the dynamics of an atom in a driven gravitational cavity. It is demonstrated that the external driving field influences the revival time significantly. Analytical expressions are presented which are based on second-order perturbation theory and semiclassical secular theory. These analytical results explain the dependence of the revival time on the characteristic parameters of the problem quantitatively in a simple way. They are in excellent agreement with numerical results. 2000 10 10.1088/1464-4266/2/5/315 Journal of Optics B: Quantum and Semiclassical Optics 2 {IOP} Publishing 668--671 5 https://doi.org/10.1088%2F1464-4266%2F2%2F5%2F315 F. Saif G. Alber V. Savichev W. P. Schleich article Meneghini2000 We present a scheme which combines focusing of atomic de Broglie waves by standing light waves and fractional Talbot imaging to produce nanostructures. Masking of the incoming atomic wave by an absorptive grating is used to eliminate atom-optical aberrations that would otherwise wash out the fractional Talbot images. The scheme allows the creation of structures of very small feature size as well as small period. 2000 5 01 1432-0649 10.1007/s003400050880 Applied Physics B 70 675--682 5 https://doi.org/10.1007/s003400050880 S. Meneghini V. I. Savichev K. A. H. van Leeuwen W. P. Schleich article Friesch_2000 The dynamics of many different quantum systems is characterized by a regular net of minima and maxima of probability stretching out in a spacetime representation. We offer an explanation to this phenomenon in terms of the Wigner function. This approach illustrates very clearly the crucial role played by interference. 2000 3 10.1088/1367-2630/2/1/004 New Journal of Physics 2 {IOP} Publishing 4--4 https://doi.org/10.1088%2F1367-2630%2F2%2F1%2F004 O. M. Friesch I. Marzoli W. P. Schleich article PhysRevA.61.032101 2000 2 10.1103/PhysRevA.61.032101 Phys. Rev. A 61 American Physical Society 032101 https://link.aps.org/doi/10.1103/PhysRevA.61.032101 A. E. Kaplan I. Marzoli W. E. Lamb W. P. Schleich inproceedings 2000 Quantum Optics of Small Structures Verh. Nat. Kon. Ned. Akad. van Wetensch D. Lenstra, T.D. Visser and K.A.H. van Leeuwen 169-183 H. Mack S. Meneghini W. P. Schleich article 2000 Laser Physics 10 116-122 S. Meneghini I. Jex K. A. H. van Leeuwen M. R. Kasimov W. P. Schleich V. P. Yakovlev inbook 2000 Decoherence: Theoretical, Experimental and Conceptual Problems Springer

Heidelberg

Ph. Blanchard, D. Giulini E. Joos C. Kiefer and I.-O. Stamatescu 179-189 F. Saif K. Riedel W. P. Schleich B. Mirbach article Schleich2000 The quantum world will always tend towards the classical world through a process known as decoherence. This is a major barrier to the success of quantum computers and quantum communication. New experiments that engineer decoherence in the laboratory throw light on what happens when a quantum system evolves into a classical system. 2000 1476-4687 10.1038/35002223 Nature 403 256-257 6767 https://doi.org/10.1038/35002223 W. P. Schleich article 2000 Laser Physics 10 123-126 K. Banaszek K. Wódkiewicz W. Schleich article doi:10.1080/09500340008232204 2000 10.1080/09500340008232204 Journal of Modern Optics 47 Taylor & Francis 2891-2904 14-15 R. Bonifacio I. Marzoli W. P. Schleich inproceedings 2000 Quantum Optics of Small Structures Verh. Nat. Kon. Ned. Akad. van Wetensch. D. Lenstra, T.D. Visser and K.A.H. van Leeuwen 195-206 K. A. H. van Leeuwen A. E. A. Koolen M. J. de Koning H. C. W. Beijerinck W. P. Schleich inbook 2000 Trends in Quantum Mechanics World Scientific

Singapur

H.-D. Doebner, S.T. Ali, M. Keyl and R.F. Werner M. Freyberger S. H. Kienle W. P. Schleich article doi:10.1063/1.481060 2000 10.1063/1.481060 The Journal of Chemical Physics 112 5060-5069 11 Ch. Warmuth A. Tortschanoff F. Milota M. Shapiro Y. Prior I. Sh. Averbukh W. Schleich W. Jakubetz H. F. Kauffmann article CZIRJAK200029 The Wigner function is used to study a simple model system for strong-field induced ionization: an electron tunneling out of a zero-range potential in the presence of a uniform static electric field. We derive an analytic expression for an approximate Wigner function describing a stationary situation where the part lost to ionization is continuously replenished. This approach is well justified by comparison with the true time dependent Wigner function obtained by numerically solving the one-dimensional problem. The three- and one-dimensional Wigner functions both suggest that the electron leaves the tunnel with a non-zero velocity. 2000 0030-4018 https://doi.org/10.1016/S0030-4018(99)00591-X Optics Communications 179 29 - 38 1 http://www.sciencedirect.com/science/article/pii/S003040189900591X A. Czirják R. Kopold W. Becker M. Kleber W. P. Schleich article PhysRevA.61.013410 1999 12 10.1103/PhysRevA.61.013410 Phys. Rev. A 61 American Physical Society 013410 https://link.aps.org/doi/10.1103/PhysRevA.61.013410 D. Bouwmeester I. Marzoli G. P. Karman W. Schleich J. P. Woerdman article Hall_1999 Generic channel and ridge structures are known to appear in the time-dependent position probability distribution of a one-dimensional quantum particle confined to a box. These structures are shown to have a detailed quantitative explanation in terms of a travelling-wave decomposition of the probability density, wherein each contributing term corresponds simultaneously to (i) a real wave propagating at a quantized velocity and (ii) to the time-averaged structure of the position distribution along a quantized direction in spacetime. The approach leads to new predictions of channel locations, widths and depths, and is able to provide more structural details than earlier approaches based on partial interference and Wigner functions. Results are also applicable to light diffracted by a periodic grating, and to the quantum rigid rotator. 1999 11 10.1088/0305-4470/32/47/307 Journal of Physics A: Mathematical and General 32 {IOP} Publishing 8275--8291 47 https://doi.org/10.1088%2F0305-4470%2F32%2F47%2F307 M. J. W. Hall M. S. Reineker W. P. Schleich article PhysRevLett.83.3162 1999 10 10.1103/PhysRevLett.83.3162 Phys. Rev. Lett. 83 American Physical Society 3162--3165 https://link.aps.org/doi/10.1103/PhysRevLett.83.3162 S. Schaufler W. P. Schleich V. P. Yakovlev article RevModPhys.71.S263 1999 3 10.1103/RevModPhys.71.S263 Rev. Mod. Phys. 71 American Physical Society S263--S273 https://link.aps.org/doi/10.1103/RevModPhys.71.S263 W. E. Lamb W. P. Schleich M. O. Scully C. H. Townes article PhysRevA.59.2163 1999 3 10.1103/PhysRevA.59.2163 Phys. Rev. A 59 American Physical Society 2163--2173 https://link.aps.org/doi/10.1103/PhysRevA.59.2163 I. Sh. Averbukh M. Shapiro C. Leichtle W. P. Schleich incollection FREYBERGER1999143 1999 1049-250X 10.1016/S1049-250X(08)60220-7 41 Academic Press Advances In Atomic, Molecular, and Optical Physics B. Bederson and H. Walther 143 - 180 M. Freyberger A. M. Herkommer D. S. Krähmer E. Mayr W. P. Schleich article PhysRevA.59.797 1999 1 10.1103/PhysRevA.59.797 Phys. Rev. A 59 American Physical Society 797--802 https://link.aps.org/doi/10.1103/PhysRevA.59.797 K. Riedel P. Törmä V. Savichev W. P. Schleich inproceedings 10.1007/978-3-642-58600-2_5 We show that quantum localization occurs in the center-of-mass motion of a two-level ion stored in a Paul trap and interacting with a standing laser field. The variable showing localization is identified to be the vibrational quantum number of a reference Floquet oscillator. The quantum localization length is shown to oscillate as a function of the atom-field detuning with a period given by the secular frequency of the trap. Furthermore, we simulate the effect of spontaneous emission on the system and show that in the limit of far detuning the phenomenon of dynamical localization is not destroyed by decoherence. 1999 978-3-642-58600-2 10.1007/978-3-642-58600-2_5 High Performance Computing in Science and Engineering '98 Springer

Berlin, Heidelberg

E. Krause and W. Jäger 35--53 K. Riedel P. Törmä V. Savichev W. P. Schleich article PhysRevA.59.718 1999 1 10.1103/PhysRevA.59.718 Phys. Rev. A 59 American Physical Society 718--727 https://link.aps.org/doi/10.1103/PhysRevA.59.718 M. Fortunato P. Tombesi W. P. Schleich article article 1999 Laser Physics 9 270-276 D. G. Fischer S. H. Kienle W. P. Schleich V. P. Yakovlev M. Freyberger article 1999 Optics and Spectroscopy 87 567-571 M. Fortunato P. Tombesi W. P. Schleich article Schleich1999 Physicists have actively manipulated the shape of a quantum wavefunction, demonstrating an unprecedented amount of control over the quantum state. In an experiment last year, researchers used a variant of quantum holography to measure the wavefunction of an atomic electron. Now they have applied this technique to produce any desired wavefunction of the atomic electron via a feedback loop. 1999 1476-4687 10.1038/16583 Nature 397 207-208 6716 https://doi.org/10.1038/16583 W. P. Schleich article 1999 Laser Physics 9 277-280 S. Schaufler W. P. Schleich V. P. Yakovlev inbook 1999 Nonlinear Dynamics and Computational Physics Narosa Publishing House

New Delhi

V. B. Sheorey 135-146 I. Marzoli I. Białynicki-Birula O. M. Friesch A. E. Kaplan W. P. Schleich article PhysRevA.59.714 1999 1 10.1103/PhysRevA.59.714 Phys. Rev. A 59 American Physical Society 714--717 https://link.aps.org/doi/10.1103/PhysRevA.59.714 M. Fortunato G. Kurizki W. P. Schleich article PhysRevA.58.4779 1998 12 10.1103/PhysRevA.58.4779 Phys. Rev. A 58 American Physical Society 4779--4783 https://link.aps.org/doi/10.1103/PhysRevA.58.4779 F. Saif I. Białynicki-Birula M. Fortunato W. P. Schleich article PhysRevA.58.4841 1998 12 10.1103/PhysRevA.58.4841 Phys. Rev. A 58 American Physical Society 4841--4853 https://link.aps.org/doi/10.1103/PhysRevA.58.4841 B. Kneer T. Wong K. Vogel W. P. Schleich D. F. Walls article PhysRevLett.80.5730 1998 6 10.1103/PhysRevLett.80.5730 Phys. Rev. Lett. 80 American Physical Society 5730--5733 https://link.aps.org/doi/10.1103/PhysRevLett.80.5730 M. Fortunato G. Kurizki W. P. Schleich article Kr_hmer_1998 We investigate a hydrogen-like atom (or any other system with a Coulomb potential) confined to a space which is bounded by a paraboloid. The nucleus of the atom resides at the focus of the paraboloid and we require the electronic wavefunction to vanish on the paraboloid. We derive an exact implicit analytic solution to the problem and also explicit analytic expressions for the wavefunctions and eigenenergies in the so-called strong-shift regime. We also discuss the influence of the boundary on the permanent dipole moments of the eigenstates. Finally, we investigate this system in WKB-approximation and give the Bohr-Sommerfeld quantization rule which is different from the usual rule due to the new boundary condition. 1998 5 10.1088/0305-4470/31/19/014 Journal of Physics A: Mathematical and General 31 {IOP} Publishing 4493--4520 19 https://doi.org/10.1088%2F0305-4470%2F31%2F19%2F014 D. S. Krähmer W. P. Schleich V. P. Yakovlev article PhysRevA.57.3188 1998 5 10.1103/PhysRevA.57.3188 Phys. Rev. A 57 American Physical Society 3188--3205 https://link.aps.org/doi/10.1103/PhysRevA.57.3188 M. Hug C. Menke W. P. Schleich article PhysRevA.57.3206 1998 5 10.1103/PhysRevA.57.3206 Phys. Rev. A 57 American Physical Society 3206--3224 https://link.aps.org/doi/10.1103/PhysRevA.57.3206 M. Hug C. Menke W. P. Schleich article Banaszek:98 A phase space description of the fractional Talbot effect, occurring in a one--dimensional Fresnel diffraction from a periodic grating, is presented. Using the phase space formalism a compact summation formula for the Wigner function at rational multiples of the Talbot distance is derived. The summation formula shows that the fractional Talbot image in the phase space is generated by a finite sum of spatially displaced Wigner functions of the source field. 1998 3 10.1364/OE.2.000169 Opt. Express 2 OSA 169--172 5 Talbot and self-imaging effects; Coherent optical effects; Fresnel diffraction; Interference; Kerr media; Phase space analysis methods; Spatial frequency; Talbot effect http://www.opticsexpress.org/abstract.cfm?URI=oe-2-5-169 B. Konrad W. Krzysztof W. P. Schleich article Hug_1998 We present a method for the direct computation of the Wigner function by solving a coupled system of linear partial differential equations in phase space. Our modified spectral method relies on Chebyshev polynomials. Since this approach allows us to include arbitrary high orders of partial derivatives, our procedure is applicable to arbitrary binding potentials. We apply our scheme to Wigner functions of the harmonic oscillator, the Morse oscillator, and an asymmetric double-well potential. 1998 3 10.1088/0305-4470/31/11/002 Journal of Physics A: Mathematical and General 31 {IOP} Publishing L217--L224 11 https://doi.org/10.1088%2F0305-4470%2F31%2F11%2F002 M. Hug C. Menke W. P. Schleich article PhysRevLett.80.1418 1998 2 10.1103/PhysRevLett.80.1418 Phys. Rev. Lett. 80 American Physical Society 1418--1421 https://link.aps.org/doi/10.1103/PhysRevLett.80.1418 C. Leichtle W. P. Schleich I. Sh. Averbukh M. Shapiro article BARDROFF1998121 We put forward an adaptive simulation method to infer the phases of nonlinear waves when the spatial amplitudes are measured over a sufficiently long time interval. 1998 0030-4018 https://doi.org/10.1016/S0030-4018(97)00655-X Optics Communications 147 121 - 125 1 http://www.sciencedirect.com/science/article/pii/S003040189700655X P. J. Bardroff U. Leonhardt W. P. Schleich article Kaplan_1998 Highly regular spatio-temporal or multi-dimensional patterns in the quantum mechanical probability or classical field intensity distributions can appear due to pair interference between individual eigen-modes of the system forming the so called intermode traces. These patterns are strongly pronounced if the intermode traces are multi-degenerate. This phenomenon occurs in many areas of wave physics. 1998 10.1238/Physica.Topical.076a00093 Physica Scripta T76 {IOP} Publishing 93 1 https://doi.org/10.1238%2Fphysica.topical.076a00093 A. E. Kaplan P. Stifter K. A. H. van Leeuwen W. E. Lamb, Jr. W. P. Schleich inproceedings 1998 Proceedings of the 5th Wigner Symposium World Scientific

Singapore

P. Kasperkovitz and D. Grau 323-329 I. Marzoli O. M. Friesch W. P. Schleich article 1998 0323-0465 Acta Phys. Slovaca 48 323-333 3 I. Marzoli F. Saif I. Białynicki-Birula O. M. Friesch A. E. Kaplan W. P. Schleich article BUZEK19981 We present a microscopic model for a grey body which consists of a blackbody at the temperature Tb surrounded by a semitransparent mirror. We derive the density operator of the grey-body radiation in the photon number or Wigner representation. These relations involve the density matrix or the Wigner function of the incident radiation and kernels which contain information about the blackbody temperature and the mirror. 1998 0375-9601 https://doi.org/10.1016/S0375-9601(98)00074-7 Physics Letters A 239 1 - 5 1 http://www.sciencedirect.com/science/article/pii/S0375960198000747 V. Bužek D. S. Krähmer M. T. Fontenelle W. P. Schleich article doi:10.1063/1.476501 1998 10.1063/1.476501 The Journal of Chemical Physics 108 6057-6067 15 C. Leichtle W. P. Schleich I. Sh. Averbukh M. Shapiro article Kienle1997 1997 12 01 1432-0649 10.1007/s003400050340 Applied Physics B 65 735--743 6 https://doi.org/10.1007/s003400050340 S. H. Kienle D. Fischer W. P. Schleich V. P. Yakovlev M. Freyberger article PhysRevA.56.4164 1997 11 10.1103/PhysRevA.56.4164 Phys. Rev. A 56 American Physical Society 4164--4174 https://link.aps.org/doi/10.1103/PhysRevA.56.4164 M. Schröder K. Vogel W. P. Schleich M. O. Scully H. Walther article Freyberger_1997 Quantum theory is undeniably one of the most powerful and successful theories in physics. For most of this century physicists have been using quantum theory to predict and explain the behaviour of light and matter in an amazing range of experiments and applications. From high-energy collisions and neutron stars to semiconductors and lasers, the theory has proven itself time and time again. 1997 11 10.1088/2058-7058/10/11/31 Physics World 10 {IOP} Publishing 41--46 11 https://doi.org/10.1088%2F2058-7058%2F10%2F11%2F31 M. Freyberger P. J. Bardroff C. Leichtle G. Schrade W. P. Schleich article PhysRevA.56.2972 1997 10 10.1103/PhysRevA.56.2972 Phys. Rev. A 56 American Physical Society 2972--2977 https://link.aps.org/doi/10.1103/PhysRevA.56.2972 Fam Le Kien G. Rempe W. P. Schleich M. S. Zubairy article Schaufler_1997 We derive and analyze scaling properties of the kinetic equation for subrecoil laser cooling. These scaling laws determine the universal asymptotic time behaviour in complete agreement with the results of the statistical analysis in terms of Lévy flights. 1997 8 10.1209/epl/i1997-00366-3 Europhysics Letters (EPL) 39 {IOP} Publishing 383--388 4 https://doi.org/10.1209%2Fepl%2Fi1997-00366-3 S. Schaufler W. P. Schleich V. P. Yakovlev article PhysRevLett.78.4181 1997 6 10.1103/PhysRevLett.78.4181 Phys. Rev. Lett. 78 American Physical Society 4181--4184 https://link.aps.org/doi/10.1103/PhysRevLett.78.4181 M. El Ghafar P. Törmä V. Savichev E. Mayr A. Zeiler W. P. Schleich article Gro_mann_1997 Recently W Kinzel [1995 Phys. Bl. 51 1190] has argued that even simple quantum systems can exhibit surprising phenomena. As an example he presented the formation of canals and ridges in the time-dependent probability density of a particle caught in a square well with infinitely high walls. We show how these structures emerge from the wavefunction and present a simple derivation of their location in the spacetime continuum. 1997 5 10.1088/0305-4470/30/9/004 Journal of Physics A: Mathematical and General 30 {IOP} Publishing L277--L283 9 https://doi.org/10.1088%2F0305-4470%2F30%2F9%2F004 F. Großmann J.-M. Rost W. P. Schleich article Kien_1997 We study the interaction of a quantized single-mode standing-wave cavity field with a two-level atom de Broglie wave. For the sake of simplicity we consider the field to be far detuned and the atom to be moving in the Raman - Nath regime. We show that the Wigner function of the field is a superposition of the Wigner functions for the coherent states aligned on an arc in phase space. The back action of the measurement of the atomic internal state leads to the modification of the diagonal as well as of the off-diagonal elements of the field density matrix. We investigate the formation of nonclassical field states via atomic deflection and internal-state measurement and show that the coherence of the field and the interference between the constituent coherent states disappear in the limit of large interaction times. The width of the atomic momentum distribution allows us to determine the mean photon number and the width of the photon distribution. We find that, for an appropriate choice of the initial state of the atomic centre-of-mass motion, the form of the atomic momentum distribution is identical to that of the photon distribution. The field near a node or an antinode acts as a focusing or defocusing lens for atoms, depending on the detuning and on the initial internal state of the atom. 1997 2 10.1088/1355-5111/9/1/006 Quantum and Semiclassical Optics: Journal of the European Optical Society Part B 9 {IOP} Publishing 69--101 1 https://doi.org/10.1088%2F1355-5111%2F9%2F1%2F006 Fam Le Kien K. Vogel W. P. Schleich article PhysRevLett.78.1195 1997 2 10.1103/PhysRevLett.78.1195 Phys. Rev. Lett. 78 American Physical Society 1195--1195 https://link.aps.org/doi/10.1103/PhysRevLett.78.1195 S. Meneghini P. J. Bardroff E. Mayr W. P. Schleich article doi:10.1080/09500349708231897 1997 10.1080/09500349708231897 Journal of Modern Optics 44 Taylor & Francis 2507-2513 11-12 A. M. Herkommer W. P. Schleich M. S. Zubairy article doi:10.1080/09500349708231886 1997 10.1080/09500349708231886 Journal of Modern Optics 44 Taylor & Francis 2333-2342 11-12 S. Schneider A. M. Herkommer U. Leonhardt W. P. Schleich article 1997 1865-7109 10.1515/zna-1997-0501 Zeitschrift für Naturforschung A 52 377-385 5 P. Stifter C. Leichtle W. P. Schleich J. Marklof article GhafarApr1997 We have shown that dynamical localization happens in the quantum motion of an ion in a Paul trap interacting with a standing wave laser field The variable which shows dynamical localization is the vibrational quantum number of a reference oscillator, which leads to localization in both momentum and position Here we discuss shortly the effect of decoherence (authors) 1997 0323-0465 47

Slovakia

291-294 3/4 http://inis.iaea.org/search/search.aspx?orig_q=RN:29064045 M. El Ghafar K. Riedel P. Törmä V. Savichev E. Mayr A. Zeiler W. P. Schleich article Schrade1997 We show that three real-valued parameters govern the quantum motion of an ion stored in the Paul trap. These parameters are two angles of rotation in phase space and a squeezing parameter. The time dependence of these parameters simplifies considerably using Floquet solutions. This allows us to use the method of quantum state endoscopy to measure a pure state of the vibratory motion of an ion taking into account the full time dependence of the trapping potential. 1997 1 01 1432-0649 10.1007/s003400050163 Applied Physics B 64 181--191 2 https://doi.org/10.1007/s003400050163 G. Schrade P. J. Bardroff R. J. Glauber C. Leichtle V. Yakovlev W. P. Schleich inbook 1997 Experimental Metaphysics Kluwer

Dordrecht

R.S. Cohen, M. Horne and J. Stachel 121-133 S. H. Kienle M. Freyberger W. P. Schleich M. G. Raymer article doi:10.1080/09500349708231860 1997 10.1080/09500349708231860 Journal of Modern Optics 44 Taylor & Francis 1985-1998 10 M. El Ghafar E. Mayr V. Savichev P. Törmä A. Zeiler W. P. Schleich article 1997 Comments in Atomic and Molecular Physics 33 145-157 3 A. M. Herkommer W. P. Schleich inbook 1997 Frontiers of Quantum Optics and Laser Physics World Scientific

Singapore

Y. S. Zhu, M. S. Zubairy and M. O. Scully 236-246 P. Stifter W. E. Lamb, Jr. W. P. Schleich article Freyberger1997 Information about a quantum system is encoded in its quantum state, a quantity whose meaning is vigorously debated. But direct insight should be gained into quantum states now that they can be mapped out. 1997 1476-4687 10.1038/386121a0 Nature 386 121-122 6621 https://doi.org/10.1038/386121a0 M. Freyberger W. P. Schleich article PhysRevA.54.5299 1996 12 10.1103/PhysRevA.54.5299 Phys. Rev. A 54 American Physical Society 5299--5312 https://link.aps.org/doi/10.1103/PhysRevA.54.5299 C. Leichtle I. Sh. Averbukh W. P. Schleich article PhysRevLett.77.3999 1996 11 10.1103/PhysRevLett.77.3999 Phys. Rev. Lett. 77 American Physical Society 3999--4002 https://link.aps.org/doi/10.1103/PhysRevLett.77.3999 C. Leichtle I. Sh. Averbukh W. P. Schleich article PhysRevLett.77.2198 1996 9 10.1103/PhysRevLett.77.2198 Phys. Rev. Lett. 77 American Physical Society 2198--2201 https://link.aps.org/doi/10.1103/PhysRevLett.77.2198 P. J. Bardroff C. Leichtle G. Schrade W. P. Schleich article PhysRevA.53.2736 1996 4 10.1103/PhysRevA.53.2736 Phys. Rev. A 53 American Physical Society 2736--2741 https://link.aps.org/doi/10.1103/PhysRevA.53.2736 P. J. Bardroff E. Mayr W. P. Schleich P. Domokos M. Brune J. M. Raimond S. Haroche article Herkommer_1996 We study a continuous homodyne measurement of the field transmitted from an optical cavity. In particular, we investigate the back-action of this measurement onto an atom whose centre-of-mass motion is entangled with the cavity field. Using the method of quantum trajectories we calculate analytically and numerically the time evolution of the entangled quantum state, and demonstrate the localization of the atom relative to the nodes of the cavity field. We compare the quantum trajectory formalism of the continuous homodyne measurement to a projection onto quadrature eigenstates of the field and show that in the long-time limit both descriptions are identical. 1996 2 10.1088/1355-5111/8/1/014 Quantum and Semiclassical Optics: Journal of the European Optical Society Part B 8 {IOP} Publishing 189--203 1 https://doi.org/10.1088%2F1355-5111%2F8%2F1%2F014 A. M. Herkommer H. J. Carmichael W. P. Schleich inbook 1996 Quantum Interferometry II VCH-Verlag

Weinheim

F. De Martini, G. Denardo and Y. Shih 451-459 M. Schröder K. Vogel W. P. Schleich F. De Martini article 1996 10.1002/phbl.19960520736 Phys. Bl. 52 736-737 7-8 Review of the book with the same title by G. Compagno, R. Passante, and F. Persico W. P. Schleich inbook 1996 Quantum Interferometry II VCH-Verlag

Weinheim

F. De Martini, G. Denardo and Y. Shih 413-427 E. Mayr V. P. Yakovlev W. P. Schleich article 1996 0323-0465 Acta Phys. Slovaca 46 373-379 M. T. Fontenelle S. L. Braunstein W. P. Schleich inproceedings 10.1007/978-1-4757-9742-8_146 We investigate the classical and quantum dynamics of atoms moving in a phase-modulated standing light field. 1996 978-1-4757-9742-8 10.1007/978-1-4757-9742-8_146 Coherence and Quantum Optics VII Springer US

Boston, MA

J. H. Eberly, L. Mandel and E. Wolf 547--548 E. Mayr P. J. Bardroff D. S. Krähmer P. Stifter I. Białynicki-Birula V. P. Yakovlev G. Kurizki W. P. Schleich inproceedings 10.1007/978-1-4757-9742-8_153 In a coherent superposition of many discrete quantum states, each contributing state evolves independently in time. Nevertheless, for short times, the dynamics of such a quantum system is almost periodic with a period T1 corresponding to the typical energy separation between neighboring eigenstates. However, for times larger than this characteristic time, this periodicity disappears and new features emerge1: At fractions of another characteristic time T2 the system is again periodic, however now, with a period which is a fraction of T1. In this note we present an analytical approach2 towards these so-called fractional revivals. 1996 978-1-4757-9742-8 10.1007/978-1-4757-9742-8_153 Coherence and Quantum Optics VII Springer US

Boston, MA

J. H. Eberly, L. Mandel and E. Wolf 561--562 C. Leichtle W. P. Schleich I. Sh. Averbukh inproceedings 10.1007/978-1-4757-9742-8_144 An atom passing through a standing electromagnetic wave inside an optical cavity couples via its dipole moment to the cavity field. The state of the combined system is an entangled state of atom and field; consequently, a measurement on one of the subsystems, on either the atom or the field, will provide information about the other. In particular, the position of the atom in the standing wave becomes strongly correlated with the phase of the field, since in the presence of the field the atom becomes polarized and thus changes the phase of the field through its refractive index; the magnitude of this phase change depends on the local light intensity and hence on the position of the atom. A measurement of the phase change due to the atom traversing the cavity can be made, for example, by balanced homodyne detection, and yields information about the position of the atom relative to the nodes and anti-nodes of the standing wave1,2. The information gain implies a localization of an initially extended atomic wave-packet. We have made a detailed investigation of this measurement-induced localization, where the influence of the measurement on the state of the system is described by the method of quantum trajectories3, which links measurement theory with quantum jump simulations. The quantum trajectory method allowed us to calculate the time evolution of the system wave function, conditioned on the measurement record made by the homodyne detector. 1996 978-1-4757-9742-8 10.1007/978-1-4757-9742-8_144 Coherence and Quantum Optics VII Springer US

Boston, MA

J. H. Eberly, L. Mandel and E. Wolf 543--544 A. M. Herkommer H. J. Carmichael W. P. Schleich inproceedings 10.1007/978-1-4757-9742-8_166 Recently, we have proposed two schemes to manipulate a quantum state of a single-mode cavity field in a controlled way by sending two-level atoms through a cavity.1,2 In one of these schemes1 a desired cavity field state is build up step by step starting from the vacuum state. Two-level atoms are prepared in a coherent superposition of the lower state and the upper state. Then the atomic coherence is transfered to the cavity field. As a two-level atom can deposit at most one photon in the cavity, we need N atoms to prepare an arbitrary superposition of N + 1 Fock states. However, probabilities enter because all two-level atoms must be detected in the lower state after they have interacted with the cavity field. In this paper we show that the idea can be generalized to atoms with more than two levels. The main advantage of this generalization is that a single atom can transfer a larger amount of coherence to the cavity field. 1996 978-1-4757-9742-8 10.1007/978-1-4757-9742-8_166 Coherence and Quantum Optics VII Springer US

Boston, MA

J. H. Eberly, L. Mandel and E. Wolf 589--590 K. Vogel W. P. Schleich G. Kurizki article 1996 Acta Phys. Slovaca 46 231-240 P. J. Bardroff C. Leichtle G. Schrade W. P. Schleich article 1996 Acta Phys. Slovaca 46 381-386 M. Fortunato W. P. Schleich G. Kurizki article Schleich1897 1996 0036-8075 10.1126/science.272.5270.1897-a Science 272 American Association for the Advancement of Science 1897--1898 5270 W. P. Schleich inproceedings 10.1007/978-1-4757-9742-8_29 In June 1960 the first in this series of most successful Rochester conferences on Coherence and Quantum Optics took place. At this meeting devoted to Coherence Properties of Electromagnetic Radiation Joe Weber presented a paper1 with the title ``Phase as a Dynamical Variable''. It is remarkable that 35 years later this question it is still such a hot topic that it is the subject of various invited and contributed papers2,3 at the seventh conference of this series. Indeed over the last years the question of a proper quantum mechanical description of phase has attracted a lot of attention. This is on one hand due to the experimental progress in creating non classical states of light which display phase properties different from those of a coherent state, and on the other hand was triggered by the Pegg-Barnett proposal for a hermitian phase operator. Moreover the recent operational approach by Noh, Foug{\`e}res, and Mandel (NFM) opened a new era in this long standing debate. There are many indications that phase will still be a major topic at the next meeting in the new millennium for which Emil Wolf had us sign up already. 1996 978-1-4757-9742-8 10.1007/978-1-4757-9742-8_29 Coherence and Quantum Optics VII Springer US

Boston, MA

Eberly, Joseph H. and Mandel, Leonard and Wolf, Emil 239--249 M. Heni M. Freyberger W. P. Schleich inproceedings ISI:A1996BG84V00008 1996 0-7503-0394-8 0309-8710 Israel Physical Society Dilemma of Einstein, Podolsky and Rosen - 60 Years Later 12 Annals of the Israel Physical Society A. Mann and M. Revzen 73-82 International Symposium on the Dilemma of Einstein, Podolsky and Rosen, in Honour of Nathan Rosen, HAIFA, ISRAEL, MAR, 1995 M. T. Fontenelle M. Freyberger M. Heni W. P. Schleich M. S. Zubairy inproceedings 10.1007/978-1-4757-9742-8_220 In a recent paper1 we have proposed the method of quantum state endoscopy to measure the complete quantum state of a single mode of the electromagnetic field. In the present article we perform numerical simulations of an experimental realization based on realistic parameters2 to demonstrate the experimental feasibility. 1996 978-1-4757-9742-8 10.1007/978-1-4757-9742-8_220 Coherence and Quantum Optics VII Springer US

Boston, MA

J. H. Eberly, L. Mandel and E. Wolf 699--700 P. J. Bardroff E. Mayr W. P. Schleich P. Domokos M. Brune J. M. Raimond S. Haroche inbook Scully1996 We dedicate this paper to our hero Charles Townes in recognition of his pioneering work in maser and laser physics as one of the many spin-offs of his great inventions. 1996 978-1-4612-2378-8 10.1007/978-1-4612-2378-8_54 Springer

New York, NY

Chiao, Raymond Y. 573--583 https://doi.org/10.1007/978-1-4612-2378-8_54 M. O. Scully W. P. Schleich H. Walther article PhysRevA.51.4963 1995 6 10.1103/PhysRevA.51.4963 Phys. Rev. A 51 American Physical Society 4963--4966 https://link.aps.org/doi/10.1103/PhysRevA.51.4963 P. J. Bardroff E. Mayr W. P. Schleich article Freyberger_1995 The authors review the operational quantum phase description of Noh, Fougeres and Mandel (1991-3) (NFM) and show that in the strong local oscillator limit it leads us to a two-mode theory of phase. This two-mode description contains the quantum phase of Paul (1993) as a special case. Furthermore this approach connects directly with a generalized and measurable phase space distribution. 1995 6 10.1088/1355-5111/7/3/001 Quantum and Semiclassical Optics: Journal of the European Optical Society Part B 7 {IOP} Publishing 187--203 3 https://doi.org/10.1088%2F1355-5111%2F7%2F3%2F001 M. Freyberger M. Heni W. P. Schleich article Schrade_1995 The authors review the theory of the harmonic oscillator with time-dependent frequency by means of an approach based on an operator constant of the motion. With the help of this operator constant we define the ground state, the excited states and a coherent state of the oscillator and discuss the time dependence of these states through their Wigner functions. The authors derive the Wigner function of an arbitrary state at time t evolving in the time-dependent harmonic potential. Moreover, they calculate the correlation coefficient between position and momentum, which appears in the Schrodinger uncertainty relation. The authors illustrate their results for the example of a charged particle in the Paul trap. 1995 6 10.1088/1355-5111/7/3/009 Quantum and Semiclassical Optics: Journal of the European Optical Society Part B 7 IOP Publishing 307--325 3 https://doi.org/10.1088%2F1355-5111%2F7%2F3%2F009 G. Schrade V. I. Man'ko W. P. Schleich R. J. Glauber article PhysRevLett.74.3959 1995 5 10.1103/PhysRevLett.74.3959 Phys. Rev. Lett. 74 American Physical Society 3959--3962 https://link.aps.org/doi/10.1103/PhysRevLett.74.3959 P. J. Bardroff I. Białynicki-Birula D. S. Krähmer G. Kurizki E. Mayr P. Stifter W. P. Schleich article PhysRevA.51.1792 1995 3 10.1103/PhysRevA.51.1792 Phys. Rev. A 51 American Physical Society 1792--1803 https://link.aps.org/doi/10.1103/PhysRevA.51.1792 M. Hillery M. Freyberger W. Schleich article Bestle1995 We show how the Wentzel-Kramers-Brillouin (WKB) approximation works for potentials with sharp corners. 1995 2 01 1432-0649 10.1007/BF01135876 Applied Physics B 60 289--299 2 https://doi.org/10.1007/BF01135876 J. Bestle W. P. Schleich J. A. Wheeler article Gallas1995 We discuss the transition probability between energy eigenstates of two displaced ``irrigation canal'' potentials in its dependence on final state energy and wall steepness. We relate the probability caught underneath the Franck-Condon maximum to the missing probability in the corresponding problem of two displaced infinitely steep and infinitely high potential wells. 1995 2 01 1432-0649 10.1007/BF01135875 Applied Physics B 60 279--287 2 https://doi.org/10.1007/BF01135875 J. A. C. Gallas W. P. Schleich J. A. Wheeler article doi:10.1111/j.1749-6632.1995.tb38995.x 1995 10.1111/j.1749-6632.1995.tb38995.x Annals of the New York Academy of Sciences 755 545-559 1 https://nyaspubs.onlinelibrary.wiley.com/doi/abs/10.1111/j.1749-6632.1995.tb38995.x D. S. Krähmer K. Vogel V. M. Akulin W. P. Schleich article 1995 10.1063/1.2808065 Physics Today 48 55-56 6 Review of book with the same title by D.F. Walls and G. Milburn Phys. Today 48, (6) 55-56 (1995) 96. M. W. P. Schleich article Mayr_Kraehmer_Herkommer_Akulin_Schleich_Averaukh_1994 1994 7 0587-4246 Acta Physica Polonica A 86 81–95 1 E. Mayr D. Krähmer V. M. Akulin A. Herkommer W. P. Schleich I. Sh. Averbukh article PhysRevA.49.5056 1994 6 10.1103/PhysRevA.49.5056 Phys. Rev. A 49 American Physical Society 5056--5066 https://link.aps.org/doi/10.1103/PhysRevA.49.5056 M. Freyberger W. Schleich article PhysRevA.49.4101 1994 5 10.1103/PhysRevA.49.4101 Phys. Rev. A 49 American Physical Society 4101--4109 https://link.aps.org/doi/10.1103/PhysRevA.49.4101 J. P. Dowling G. S. Agarwal W. P. Schleich article PhysRevA.49.3127 1994 4 10.1103/PhysRevA.49.3127 Phys. Rev. A 49 American Physical Society 3127--3130 https://link.aps.org/doi/10.1103/PhysRevA.49.3127 A. M. Herkommer V. M. Akulin W. P. Schleich article PhysRevA.49.1562 1994 3 10.1103/PhysRevA.49.1562 Phys. Rev. A 49 American Physical Society 1562--1566 https://link.aps.org/doi/10.1103/PhysRevA.49.1562 M. O. Scully H. Walther W. P. Schleich article 1994 Phys. Bl. 50 717 Review of book with the same title by J.A. Wheeler W. Schleich inproceedings 10.1007/978-3-642-79101-7_10 We consider the deflection and focusing of atoms in a quantized light field. We study the influence of spontaneous emission on the deflection pattern and propose a method to create narrow atomic wave packets. A possible experiment is suggested. 1994 978-3-642-79101-7 Quantum Optics VI Springer

Berlin, Heidelberg

D. F. Walls and J. D. Harvey 87--102 D. S. Krähmer A. M. Herkommer E. Mayr V. M. Akulin I. Sh. Averbukh T. Leeuwen V. P. Yakovlev W. Schleich inbook 1994 Current Trends in Optics II Academic Press Boston J. C. Dainty 37-50 D. Krähmer E. Mayr K. Vogel W. P. Schleich article 1994 Phys. Bl. 50 469 W. Schleich H. D. Vollmer article 1994 10.1063/1.2808653 Phys. Today 47 118 9 H. Haken W. Schleich H. D. Vollmer inproceedings 1994 Proceedings of the Third International Workshop on Squeezed States and Uncertainty Relations NASA Conference Publication

Goddard Space Flight Center

M. H. Rubin and Y.-H. Shih G. Schrade V. M. Akulin V. I. Man'ko W. P. Schleich article PhysRevLett.72.437 1994 1 10.1103/PhysRevLett.72.437 Phys. Rev. Lett. 72 American Physical Society 437--441 https://link.aps.org/doi/10.1103/PhysRevLett.72.437 I. Sh. Averbukh V. M. Akulin W. P. Schleich article doi:10.1080/09500349414551721 1994 10.1080/09500349414551721 Journal of Modern Optics 41 Taylor & Francis 1765-1779 9 S. Schaufler M. Freyberger W. P. Schleich article PhysRevA.48.2398 1993 9 10.1103/PhysRevA.48.2398 Phys. Rev. A 48 American Physical Society 2398--2406 https://link.aps.org/doi/10.1103/PhysRevA.48.2398 G. Schrade V. M. Akulin V. I. Man'ko W. P. Schleich article PhysRevLett.71.1816 1993 9 10.1103/PhysRevLett.71.1816 Phys. Rev. Lett. 71 American Physical Society 1816--1819 https://link.aps.org/doi/10.1103/PhysRevLett.71.1816 K. Vogel V. M. Akulin W. P. Schleich article PhysRevA.48.803 1993 7 10.1103/PhysRevA.48.803 Phys. Rev. A 48 American Physical Society 803--812 https://link.aps.org/doi/10.1103/PhysRevA.48.803 Tran Quang G. S. Agarwal J. Bergou M. O. Scully H. Walther K. Vogel W. P. Schleich article PhysRevA.48.813 1993 7 10.1103/PhysRevA.48.813 Phys. Rev. A 48 American Physical Society 813--817 https://link.aps.org/doi/10.1103/PhysRevA.48.813 K. Vogel W. P. Schleich M. O. Scully H. Walther article PhysRevA.48.746 1993 7 10.1103/PhysRevA.48.746 Phys. Rev. A 48 American Physical Society 746--751 https://link.aps.org/doi/10.1103/PhysRevA.48.746 J. Bestle V. M. Akulin W. P. Schleich article PhysRevA.47.4258 1993 5 10.1103/PhysRevA.47.4258 Phys. Rev. A 47 American Physical Society 4258--4269 https://link.aps.org/doi/10.1103/PhysRevA.47.4258 M. Fleischhauer W. P. Schleich article Freyberger_1993 The authors present an exact expression for the joint count probability in an eight-port homodyne detector used in a recent proposal for a phase measurement by Noh et al. (1992). For a strong local oscillator they relate this joint count probability to the Q-function of the arbitrary input state. This Q-function integrated over radius is the phase distribution corresponding to the phase operators of Noh et al. 1993 4 10.1088/0954-8998/5/2/001 Quantum Optics: Journal of the European Optical Society Part B 5 {IOP} Publishing 65--67 2 https://doi.org/10.1088%2F0954-8998%2F5%2F2%2F001 M. Freyberger K. Vogel W. Schleich article Benedict1993 Based on the exactly solvable case of a harmonic oscillator, we show that the direct correspondence between the Bohr-Sommerfeld phase of semiclassical quantum mechanics and the topological phase of Aharonov and Anandan is restricted to the case of a coherent state. For other Gaussian wave packets the geometric quantum phase strongly depends on the amount of squeezing. 1993 3 01 1572-9516 10.1007/BF01883719 Foundations of Physics 23 389--397 3 https://doi.org/10.1007/BF01883719 M. G. Benedict W. Schleich inproceedings 1993ssurwork29A 1993 3 Proceedings of the Second International Workshop on Squeezed States and Uncertainty Relations Nasa Conference Publication

Goddard Space Flight Center

D. Han, Y.S. Kim and V.I. Man'ko 329-339 Angular Momentum, Atomic Energy Levels, Electromagnetic Fields, Light Transmission, Quantum Theory, Squeezed States (Quantum Theory), Wigner Coefficient, Atomic Structure, Distribution Functions, Phase-Space Integral, Quantum Mechanics, Spherical Coordinates G. S. Agarwal J. P. Dowling W. P. Schleich article doi:10.1002/phbl.19930491212 Abstract Zwei wichtige Methoden, um den Zustand eines Quantensystems vollständig zu untersuchen, sind die „tomographische Methode”︁ und die „simultane Messung„. Mit ihnen lassen sich Phasenraumfunktionen rekonstruieren, die die volle Information über diesen Zustand enthalten. 1993 10.1002/phbl.19930491212 Physikalische Blätter 49 1109-1111 12 https://onlinelibrary.wiley.com/doi/abs/10.1002/phbl.19930491212 M. Freyberger W. Schleich article FREYBERGER199341 We derive an exact expression for the joint count probability in an eight-port homodyne detector, when the signal field is in an arbitrary state, the local oscillator is in a coherent state and the other two input states are the vacuum. In the limit of a strong local oscillator this photon count statistics is the scaled Q-function of the signal state. The phase distribution corresponding to this measurement scheme is then the Q-function of the signal field integrated over radius. The physical reason for the Q-function lies in the simultaneous measurement of two two-mode operators. We discuss the dependence of the photon count statistics on the local oscillator intensity using the example of a one-photon Fock state. 1993 0375-9601 https://doi.org/10.1016/0375-9601(93)90313-O Physics Letters A 176 41 - 46 1 http://www.sciencedirect.com/science/article/pii/037596019390313O M. Freyberger K. Vogel W. P. Schleich article PhysRevA.47.R30 1993 1 10.1103/PhysRevA.47.R30 Phys. Rev. A 47 American Physical Society R30--R33 https://link.aps.org/doi/10.1103/PhysRevA.47.R30 M. Freyberger W. Schleich inproceedings 1993 Symposium on the Foundations of Modern Physics World Scientific

Singapore

P. Busch, P. Lahti and P. Mittelstaedt 369-377 K. Vogel V. M. Akulin W. Schleich article Bialynicki_Birula_1993 We compare and contrast five measures of phase uncertainty of a quantum state corresponding to a single mode of the electromagnetic field. The basis of this study are the states which minimize a particular measure for a fixed number of Fock states and normalization. We find these optimal states and study their characteristic properties. These optimal states allow us to establish an ordering of the different definitions for phase uncertainty. 1993 1 10.1088/0031-8949/1993/t48/017 Physica Scripta T48 {IOP} Publishing 113--118 https://doi.org/10.1088%2F0031-8949%2F1993%2Ft48%2F017 I. Białynicki-Birula M. Freyberger W. P. Schleich article doi:10.1002/phbl.19930491213 Abstract Ein Forschungsschwerpunkt der Quantenoptik ist die Erzeugung von nichtklassischem Licht und das Studium seiner Eigenschaften. Die Herstellung solcher Zustände beschränkte sich bis jetzt auf einige typische Beispiele. Als Quantenoptiker wünscht man sich zu Weihnachten besonders „schöne”︁ Feldzustände, für die es nicht so ganz klar ist, wie man sie konstruieren kann. Um solchen Wünschen entgegenzukommen, beschreiben wir hier ein Verfahren, das es im Prinzip erlaubt, einen beliebigen Zustand für das elektromagnetische Feld aufzubauen. Wir veranschaulichen diese Methode am Beispiel eines Phasenzustands. 1993 10.1002/phbl.19930491213 Physikalische Blätter 49 1111-1112 12 https://onlinelibrary.wiley.com/doi/abs/10.1002/phbl.19930491213 K. Vogel V. M. Akulin W. Schleich article PhysRevLett.69.3298 1992 12 10.1103/PhysRevLett.69.3298 Phys. Rev. Lett. 69 American Physical Society 3298--3301 https://link.aps.org/doi/10.1103/PhysRevLett.69.3298 A. M. Herkommer V. M. Akulin W. P. Schleich article PhysRevA.46.5363 1992 11 10.1103/PhysRevA.46.5363 Phys. Rev. A 46 American Physical Society 5363--5366 https://link.aps.org/doi/10.1103/PhysRevA.46.5363 A. Mann M. Revzen W. Schleich article PhysRevA.46.4110 1992 10 10.1103/PhysRevA.46.4110 Phys. Rev. A 46 American Physical Society 4110--4113 https://link.aps.org/doi/10.1103/PhysRevA.46.4110 V. M. Akulin W. P. Schleich article PhysRevA.45.6652 1992 5 10.1103/PhysRevA.45.6652 Phys. Rev. A 45 American Physical Society 6652--6654 https://link.aps.org/doi/10.1103/PhysRevA.45.6652 W. Schleich A. Bandilla article AGARWAL1992359 We show that by using Wigner functions one can develop a treatment of the Einstein-Podolsky-Rosen correlated state of two spin 12 systems in a form similar to that of a local hidden variable model. The quantum mechanical results are exactly reproduced at the cost of allowing the probability distribution function to become negative. 1992 0375-9601 https://doi.org/10.1016/0375-9601(92)90887-R Physics Letters A 170 359 - 362 5 http://www.sciencedirect.com/science/article/pii/037596019290887R G. S. Agarwal D. Home W. Schleich inproceedings 1992 Proceedings of the 2nd Wigner Symposium World Scientific

Singapur

H.D. Doebner, W. Scherer and F. Schroeck 91-103 K. Vogel W. P. Schleich G. Süßmann H. Walther article BENARYEH1992259 We investigate the collapse of the atomic dipole caused by a squeezed vacuum in an ideal one-mode cavity. The difference between the collapse times of the two quadrature components of the dipole moments is increasing with increasing squeezing parameter. This phenomenon predicted by a hamiltonian Jaynes-Cummings model is similar to the inhibition and enhancement of atomic phase decay predicted by Gardiner for a markovian system. 1992 0030-4018 https://doi.org/10.1016/0030-4018(92)90272-S Optics Communications 90 259 - 264 4 http://www.sciencedirect.com/science/article/pii/003040189290272S Y. Ben-Aryeh C. A. Miller H. Risken W. Schleich inbook 1992 Fundamental Systems in Quantum Optics Elsevier

Amsterdam

J. Dalibard, J. M. Raimond and J. Zinn-Justin 713-765 K. Vogel W. P. Schleich inproceedings 1992 1 Proceedings of the first William Fairbanks meeting on Relativity and Gravitational Experiments in Space World Scientific

Singapur

R. Ruffini Gravitation Theory: Tests H. Heitmann W. P. Schleich M. O. Scully article PhysRevA.44.7642 1991 12 10.1103/PhysRevA.44.7642 Phys. Rev. A 44 American Physical Society 7642--7646 https://link.aps.org/doi/10.1103/PhysRevA.44.7642 W. Vogel W. Schleich article PhysRevA.44.5992 1991 11 10.1103/PhysRevA.44.5992 Phys. Rev. A 44 American Physical Society 5992--5996 https://link.aps.org/doi/10.1103/PhysRevA.44.5992 M. O. Scully H. Walther G. S. Agarwal Tran Quang W. Schleich article PhysRevA.44.3365 1991 9 10.1103/PhysRevA.44.3365 Phys. Rev. A 44 American Physical Society 3365--3368 https://link.aps.org/doi/10.1103/PhysRevA.44.3365 W. P. Schleich J. P. Dowling R. J. Horowicz article PhysRevA.44.R1462 1991 8 10.1103/PhysRevA.44.R1462 Phys. Rev. A 44 American Physical Society R1462--R1465 https://link.aps.org/doi/10.1103/PhysRevA.44.R1462 V. M. Akulin Fam Le Kien W. P. Schleich article PhysRevA.44.2172 1991 8 10.1103/PhysRevA.44.2172 Phys. Rev. A 44 American Physical Society 2172--2187 https://link.aps.org/doi/10.1103/PhysRevA.44.2172 W. Schleich M. Pernigo Fam Le Kien article PhysRevA.43.3854 1991 4 10.1103/PhysRevA.43.3854 Phys. Rev. A 43 American Physical Society 3854--3861 https://link.aps.org/doi/10.1103/PhysRevA.43.3854 C. M. Caves Ch. Zhu G. J. Milburn W. Schleich inproceedings 1991 Proceedings of the Workshop on Squeezed States and Uncertainty Relations Nasa Conference Publication

Goddard Space Flight Center

D. Han, Y.S. Kim and W. W. Zachary 299-309 W. P. Schleich J. P. Dowling R. J. Horowicz article 1991 10.1063/1.2810308 Phys. Today 10 44 146-148 W. P. Schleich G. Süßmann article doi:10.1002/andp.19915030702 Abstract A central problem in quantum mechanics is the calculation of the overlap, that is, the scalar product between two quantum states. In the semiclassical limit (Bohr's correspondence principle) we visualize this quantity as the area of overlap between two bands in phase space. In the case of more than one overlap the contributing amplitudes have to be combined with a phase difference again determined by an area in phase space. In this sense the familiar double-slit interference experiment is generalized to an interference in phase space. We derive this concept by the WKB approximation, illustrate it by the example of Franck-Condon transitions in diatomic molecules, and compare it with and contrast it to Wigner's concept of pseudo-probabilities in phase space. 1991 978-3-540-47901-7 10.1002/andp.19915030702 The Physics of Phase Space Nonlinear Dynamics and Chaos Geometric Quantization, and Wigner Function Annalen der Physik 503 Springer Berlin Heidelberg

Berlin, Heidelberg

Kim, Y. S. and Zachary, W. W. 423-478 7 https://onlinelibrary.wiley.com/doi/abs/10.1002/andp.19915030702 J. P. Dowling W. P. Schleich J. A. Wheeler article doi:10.1002/phbl.19910470707 Abstract „Erst die Theorie entscheidet darüber, was man beobachten kann.”︁ Diese Bemerkung richtete Albert Einstein im Frühjahr 1926 an Werner Heisenberg im Anschluß an dessen Kolloquiumsvortrag in Berlin. Damals galt es einen scheinbaren Widerspruch zwischen Theorie und Experiment aufzulösen: Auf der einen Seite verbietet der Formalismus der Quantenmechanik und insbesondere die Kommutatorbeziehung zwischen Ort und Impuls eines Teilchens die Existenz einer Trajektorie. Andererseits beobachtet man diese in einer Wilson-Blasenkammer. Die Auflösung dieses scheinbaren Widerspruchs gelang Heisenberg mit Hilfe der Unbestimmtheitsrelation. – Heute entscheidet die Unbestimmtheitsrelation zwischen elektrischem und magnetischem Feld, d. h. die Fluktuationen in der Amplitude und der Phase des elektromagnetischen Feldes in einem Michelson-Interferometer über die prinzipielle Beobachtbarkeit einer winzigen Gravitationswelleninduzierten Phasenverschiebung. Dies hat die Entwicklung quantenrausch-verminderter Zustände des Strahlungsfeldes, der gequetschten (engl. squeezed) Zustände, motiviert und ein neues Gebiet der Quantenoptik geschaffen. Ähnlich haben die Überlegungen, die Existenz von bevorzugten Bezugsystemen und von Mitführeffekten mittels des Sagnac-Effektes nachweisen zu wollen, auf einen neuen Typ von Laser geführt, der frei von spontaner Emission ist. – In der vorliegenden Arbeit wollen wir diesen Weg vom Sagnac-Effekt, der ursprünglich als Äthernachweis konzipiert war, zu squeezed Zuständen und zum rauschfreien Laser mit korrelierter Spontanemission, d. h. zu neuem Licht nachzeichnen. Die oszillierende Photonenstatistik eines gequetschten Zustandes und ihre Interpretation als Interferenz im Phasenraum bildet den Abschluß unserer Wanderung vom Ätherwind zu neuem Licht. 1991 10.1002/phbl.19910470707 Physikalische Blätter 47 595-601 7 https://onlinelibrary.wiley.com/doi/abs/10.1002/phbl.19910470707 W. P. Schleich article PhysRevA.42.1703 1990 8 10.1103/PhysRevA.42.1703 Phys. Rev. A 42 American Physical Society 1703--1711 https://link.aps.org/doi/10.1103/PhysRevA.42.1703 B. Yurke W. Schleich D. F. Walls article PhysRevA.42.1503 1990 8 10.1103/PhysRevA.42.1503 Phys. Rev. A 42 American Physical Society 1503--1514 https://link.aps.org/doi/10.1103/PhysRevA.42.1503 C. Benkert M. O. Scully W. Schleich A. A. Rangwala article PhysRevA.41.3950 1990 4 10.1103/PhysRevA.41.3950 Phys. Rev. A 41 American Physical Society 3950--3959 https://link.aps.org/doi/10.1103/PhysRevA.41.3950 R. G. K. Habiger H. Risken M. James F. Moss W. Schleich article doi:10.1002/andp.19905020805 Abstract We demonstrate how the two-photon correlated emission laser (CEL) can be understood from a simple physical picture in a quasirigorous fashion. We use semiclassical arguments to derive correct expressions for the phase and amplitude diffusion in a simple way. We then illustrate how noise suppression is achieved in the two-photon CEL. 1990 10.1002/andp.19905020805 Annalen der Physik 502 649-658 8 https://onlinelibrary.wiley.com/doi/abs/10.1002/andp.19905020805 C. Benkert W. Schleich M. O. Scully inbook 1990 New Frontiers in QED and Quantum Optics Plenum Press

New York

A. Barut 31-61 W. Schleich J. P. Dowling R. J. Horowicz S. Varro article 1990 Spektrum der Wissenschaft 106 W. Quint W. Schleich H. Walther inbook doi:10.1142/9789812819895_0035 Abstract We review our recent work on the one-atom maser. We propose and analyse an experiment based on this maser and designed to probe the way in which the measurement process, that is, the presence of a detector influences the investigated quantum system. Phase transitions between chaotic and ordered structures of ions stored in a Paul trap are analysed. 1990 978-1-4684-1342-7 10.1142/9789812819895_0035 Foundations of Quantum Mechanics in the Light of New Technology Springer US

Boston, MA

W. Demtröder and M. Inguscio 336-346 https://doi.org/10.1007/978-1-4684-1342-7_2 G. Rempe W. Schleich M. O. Scully H. Walther article refId0 1990 10.1051/epn/19902102031 Europhys. News 21 31-33 2 https://doi.org/10.1051/epn/19902102031 W. Schleich H. Walther article PhysRevA.40.7405 1989 12 10.1103/PhysRevA.40.7405 Phys. Rev. A 40 American Physical Society 7405--7408 https://link.aps.org/doi/10.1103/PhysRevA.40.7405 W. Schleich R. J. Horowicz S. Varro article Qunit_1989 A single ion at rest, unperturbed by its environment and forced into such a state for hours – once only a physicist's dream – has now been achieved by the combination of electromagnetic traps and laser technology. The Penning trap and the dynamical Paul trap developed in the 1930s and the late 1950s respectively, provide the experimenter with a unique tool to isolate a single ion from its surroundings. Tunable lasers can then be used to force the ion to fluoresce; simultaneously, as will be described, it is cooled to milli- or even micro-Kelvin temperatures. An ion driven into saturation by a sufficiently high laser intensity so that it spends half of the time in the excited state and half in the ground state, scatters roughly 108 photons per second. This leads to a high detection probability and at the same time to a reduction of the ion's kinetic energy via photon recoil. 1989 8 10.1088/2058-7058/2/8/22 Physics World 2 {IOP} Publishing 30--34 8 https://doi.org/10.1088%2F2058-7058%2F2%2F8%2F22 W. Quint W. Schleich H. Walther inproceedings 1989 Proceedings of the Eleventh International Conference on Atomic Physics World Scientific

Singapur

S. Haroche, J.C. Gay and G. Grynberg 457-465 C. Benkert W. Schleich M. O. Scully inproceedings 1989 978-3-642-74953-7 0930-8989 Quantum Optics V Proceedings of the Fifth International Symposium Rotorua, New Zealand, February 13–17, 1989 41 Springer

Berlin, Heidelberg

Springer Proceedings in Physics J.D. Harvey and D. F. Walls 133-142 W. Schleich R. J. Horowicz S. Varro article Schleich1989 1989 1476-4687 10.1038/339257a0 Nature 339 257-258 6222 https://doi.org/10.1038/339257a0 W. Schleich P. V. E. McClintock article 1989 La Recherche 20 1194-1203 W. Quint W. Schleich H. Walther inproceedings 1989nnds....2..271V 1989 Noise in nonlinear dynamical systems 2 Cambridge University Press

Cambridge and New York

F. Moss and P.V.E. McClintock 271-292 Laser Gyroscopes, Noise Spectra, Ring Lasers, White Noise, Beat Frequencies, Fokker-Planck Equation, Langevin Formula, Laser Interferometry, Wave Propagation K. Vogel H. Risken W. Schleich inbook Schleich1989 Motion of an electron around a nucleus or, in its most elementary version, vibratory motion of a harmonic oscillator viewed in Planck-Bohr-Sommerfeld quantized phase space;1--3 and matching the discrete, microscopic world with the continuous, macroscopic world via Bohr's correspondence principle,4--5 these are the essential ingredients of ``Atommechanik''.4 Combined with the concept of interference - expressed in the familiar double-slit experiment6 - these central ideas of early quantum mechanics provide in the present paper the most vivid sources of insight into the photon count probability, Wm, of a coherent state7--9 shown in Fig. 1 and into the oscillatory10--15 photon statistics16 of a highly squeezed stat17 of a single mode of the electromagnetic field depicted in Fig. 2. 1989 978-1-4757-6574-8 10.1007/978-1-4757-6574-8_10 Squeezed and Non-Classical Light 190 Springer US

Boston, MA

NATO ASI Series (Series B: Physics) P. Tombesi and E. R. Pike 129--149 https://doi.org/10.1007/978-1-4757-6574-8_10 W. P. Schleich inproceedings 1989 Proceedings of the Eleventh International Conference on Atomic Physics World Scientific

Singapur

S. Haroche, J.C. Gay and G. Grynberg 243-259 R. Blümel J. M. Chen F. Diedrich E. Peik W. Quint W. Schleich Y. R. Shen H. Walther inbook Orszag1989 As originally conceived a correlated spontaneous emission laser showed quenching of spontaneous emission quantum fluctuations in the relative phase angle of a two mode laser. It has been shown by several approaches (e.g. quantum noise operator, Fokker-Planck equation, etc.) that such devices can, in principle, have vanishing noise in this relative phase angle. A geometric pictorial analysis along these lines has been given and provides a simple intuitive explanation for this quantum noise quenching which has also been supported by recent experimental investigations. 1989 978-1-4757-6574-8 10.1007/978-1-4757-6574-8_21 Squeezed and Non-Classical Light 190 Springer US

Boston, MA

NATO ASI Series (Series B: Physics) P. Tombesi and E. R. Pike 287--299 https://doi.org/10.1007/978-1-4757-6574-8_21 M. Orszag J. Bergou W. Schleich M. O. Scully article Schleich1988 We consider an oscillator subjected to a sudden change in equilibrium position or in effective spring constant, or both---to a ``squeeze'' in the language of quantum optics. We analyze the probability of transition from a given initial state to a final state, in its dependence on final-state quantum number. We make use of five sources of insight: Bohr-Sommerfeld quantization via bands in phase space, area of overlap between before-squeeze band and after-squeeze band, interference in phase space, Wigner function as quantum update of B-S band and near-zone Fresnel diffraction as mockup Wigner function. 1988 10 01 1572-9516 10.1007/BF01909932 Found. Phys. 18 953--968 10 https://doi.org/10.1007/BF01909932 W. Schleich H. Walther J. A. Wheeler article PhysRevA.38.1177 1988 8 10.1103/PhysRevA.38.1177 Phys. Rev. A 38 American Physical Society 1177--1186 https://link.aps.org/doi/10.1103/PhysRevA.38.1177 W. Schleich D. F. Walls J. A. Wheeler article PhysRevA.37.3010 1988 4 10.1103/PhysRevA.37.3010 Phys. Rev. A 37 American Physical Society 3010--3017 https://link.aps.org/doi/10.1103/PhysRevA.37.3010 W. Schleich M. O. Scully H.-G. Garssen article PhysRevA.37.1261 1988 2 10.1103/PhysRevA.37.1261 Phys. Rev. A 37 American Physical Society 1261--1269 https://link.aps.org/doi/10.1103/PhysRevA.37.1261 W. Schleich M. O. Scully article Bluemel1988 Single ions in miniature traps can be imaged by using laser light to stimulate fluorescence radiation. At the same time, radiation pressure can be used to bring them nearly to rest. When a small number of ions are trapped, phase transitions can be observed between a chaotic cloud and an ordered crystalline structure, depending on the degree of laser cooling. 1988 1476-4687 10.1038/334309a0 Nature 334 309-313 6180 https://doi.org/10.1038/334309a0 R. Blümel J. M. Chen E. Peik W. Quint W. Schleich Y. R. Shen H. Walther article Schleich:87 We show that the photon distribution of a highly squeezed state exhibits oscillations. 1987 10 10.1364/JOSAB.4.001715 J. Opt. Soc. Am. B 4 OSA 1715--1722 10 Coherent states; Mathematical methods; Phase space analysis methods; Photons; Quantum fluctuations; Squeezed states http://josab.osa.org/abstract.cfm?URI=josab-4-10-1715 W. Schleich J. A. Wheeler article PhysRevA.35.4882 1987 6 10.1103/PhysRevA.35.4882 Phys. Rev. A 35 American Physical Society 4882--4885 https://link.aps.org/doi/10.1103/PhysRevA.35.4882 K. Vogel Th. Leiber H. Risken P. Hänggi W. Schleich article PhysRevA.35.2532 1987 3 10.1103/PhysRevA.35.2532 Phys. Rev. A 35 American Physical Society 2532--2541 https://link.aps.org/doi/10.1103/PhysRevA.35.2532 T. Hellmuth H. Walther A. Zajonc W. Schleich article doi:10.1063/1.339751 1987 10.1063/1.339751 J. Appl. Phys. 62 721-723 2 K. Vogel H. Risken W. Schleich M. James F. Moss R. Mannella P. V. E. McClintock inbook PhaseSpace1987 1987 978-3-540-47901-7 10.1007/3-540-17894-5_346 The Physics of Phase Space Nonlinear Dynamics and Chaos Geometric Quantization, and Wigner Function 278 Springer

Berlin, Heidelberg

Lecture Notes in Physics Y.S. Kim and W.W. Zachary W. Schleich J. A. Wheeler article Schleich1987 The drive for both noise-free message transmission1,2 and high precision gravity wave detection3,4 has stimulated immense effort on a key element, a squeezed state5,6 of the electromagnetic field. Such non-classical states have been investigated theoretically in great detail1-7 and have now been realized experimentally in four laboratories in the United States8-13. However, nowhere in the literature have we been able to find the striking feature of a squeezed state which we report here: an oscillatory distribution in photon number14,15. These oscillations, and the conditions which produce them, came to light in the course of an investigation of sudden transitions16 (the Franck-Condon effect in molecular physics17,18) based on the semi-classical description of a quantum state19 as motion of a representative point in the phase space defined by oscillator coordinate and oscillator momentum. 1987 1476-4687 10.1038/326574a0 Nature 326 574-577 6113 https://doi.org/10.1038/326574a0 W. Schleich J. A. Wheeler inproceedings 1987 Foundations of quantum mechanics in the light of new technology, Proceedings of the Second International Symposium on Foundations of Quantum Mechanics Physical Society of Japan

Tokyo

K. Kamiyama 25--35 W. Schleich H. Walther article PhysRevA.35.463 1987 1 10.1103/PhysRevA.35.463 Phys. Rev. A 35 American Physical Society 463--465 https://link.aps.org/doi/10.1103/PhysRevA.35.463 K. Vogel H. Risken W. Schleich M. James F. Moss P. V. E. McClintock inproceedings 10.1007/978-3-540-47973-4_35 The arena of space-time and metric gravity is a grand playground for modern quantum optical scientists. Work in this field defines the cutting edge of technology, from precision interferometry to the quantum ``limits'' of measurement. 1987 978-3-540-47973-4 10.1007/978-3-540-47973-4_35 Laser Spectroscopy VIII Springer Series in Optical Sciences 55 Springer

Berlin, Heidelberg

W. Persson and S. Svanberg 139--142 J. Gea-Banacloche W. Schleich M. O. Scully inproceedings pedrotti1985 1986 10.1117/12.976087 Proceedings of the Southwest Conference on Optics, Albuquerque 1985 0540 SPIE

Bellingham

S. Stotlar L. M. Pedrotti W. Schleich M. O. Scully inbook Schleich1986 In the year 1851 Foucault demonstrated that the slow rotation of the plane of vibration of a pendulum could be used as evidence of the earth's own rotation. Nowadays high precision measurements of the earth's rotation are performed by using radio telescopes in Very Long Baseline interferometry [1]. However, a recent proposal [2] takes advantage of the ultra high sensitivity of a ring laser gyroscope [3] of 10m diameter to monitor changes in earth rate* or Universal time. The underlying principle of such a device is the optical analogue of the Foucault pendulum, the so-called Sagnac effect [5,6]. The frequencies of two counterpropagating waves in a ring interferometer are slightly different when the interferometer is rotating about an axis perpendicular to its plane. Since this frequency difference is proportional to the rotation rate it provides a direct measure of the rotation of the system. 1986 978-1-4613-2181-1 10.1007/978-1-4613-2181-1_27 Frontiers of Nonequilibrium Statistical Physics 135 Springer US

Boston, MA

NATO ASI Series (Series B: Physics) G.T. Moore and M. O. Scully 385--408 https://doi.org/10.1007/978-1-4613-2181-1_27 W. Schleich P. Dobiasch V. E. Sanders M. O. Scully article RevModPhys.57.61 1985 1 10.1103/RevModPhys.57.61 Rev. Mod. Phys. 57 American Physical Society 61--104 https://link.aps.org/doi/10.1103/RevModPhys.57.61 W. W. Chow J. Gea-Banacloche V. E. Sanders W. Schleich M. O. Scully inproceedings Scully:1982fn 1984 New Trends in Atomic Physics Proceedings of the Les Houches Summer School, Session XXXVIII, 1982 North Holland Physics Publ.

Amsterdam

R. Stora and G. Grynberg 995-1124 W. Schleich M. O. Scully article SCHLEICH198463 A “universal” formalism is presented which allows to treat quantum noise in a ring-laser gyroscope in the presence of any arbitrary, periodic and symmetric dither. An exact expression for the mean beat frequency ⤤Æ↩F↩t in terms of infinite matrix continued fractions is obtained. The results are applied to a square-wave dithered gyroscope. 1984 0030-4018 https://doi.org/10.1016/0030-4018(84)90074-9 Opt. Commun. 52 63 - 68 1 http://www.sciencedirect.com/science/article/pii/0030401884900749 W. Schleich P. Dobiasch article PhysRevA.29.230 1984 1 10.1103/PhysRevA.29.230 Phys. Rev. A 29 American Physical Society 230--238 https://link.aps.org/doi/10.1103/PhysRevA.29.230 W. Schleich C.-S. Cha J. D. Cresser inproceedings 10.1007/978-1-4757-0605-5_135 The new generation of ring-laser gyroscopes1 can compete with their mechanical counterparts. They can now operate down to a small fraction of earth rotation rate using rings of 1-m diameter, which makes them interesting for tests of metric gravitation theories.2 They have reached a sensitivity where the noise limit is only due to the quantum fluctuations, which arise from spontaneous emission of the laser atoms. Whereas all kinds of mechanical noise can be circumvented by some ``tricky'' techniques, there is no way around the quantum noise, which stems from the quantization of the electric field in the resonator. The final limitation of ring-laser gyroscopes is thus given by the quantum noise.3 Therefore it is important to understand this effect in detail. 1984 978-1-4757-0605-5 10.1007/978-1-4757-0605-5_135 Coherence and Quantum Optics V Springer US

Boston, MA

L. Mandel and E. Wolf 915--922 W. Schleich M. O. Scully V. Sanders article PhysRevA.25.2214 1982 4 10.1103/PhysRevA.25.2214 Phys. Rev. A 25 American Physical Society 2214--2225 https://link.aps.org/doi/10.1103/PhysRevA.25.2214 J. D. Cresser W. H. Louisell P. Meystre W. Schleich M. O. Scully