2021

Picture from the Publication

Framework for resource quantification in infinite-dimensional general probabilistic theories, L. Lami, B. Regula, R. Takagi, and G. Ferrari, Phys. Rev. A 103, 032424
DOI: doi.org/10.1103/PhysRevA.103.032424

The gist of it

It is well established that several features of quantum mechanical systems with no classical counterparts can be exploited as resources in practical applications, such as communication, computation, sensing and cryptography. It is then of paramount importance to rigorously quantify such an advantage, especially in relation to some explicit task that one might want to perform in a realistic scenario. In these two papers, we study the (generalized) robustness as a measure of a very large family of generic quantum resources, and its relation with a key task in quantum information: quantum channel discrimination. In particular, we prove that the robustness precisely quantifies the maximum advantage given by a resourceful state with respect to any free one, when used as a probe to determine which physical evolution it underwent. Our framework can be applied well beyond standard finite-dimensional quantum theory, and in particular, to all finite- and infinite-dimensional general probabilistic theories, i.e., generalizations of quantum mechanics itself. This is interesting both from a fundamental and practical perspective, as many resources needed for quantum technologies, e.g. nonclassicality and non-Gaussianity, are peculiar of systems with an associated infinite-dimensional Hilbert space.

Picture from the Publication

Operational Quantification of Continuous-Variable Quantum Resources, B. Regula, L. Lami, G. Ferrari, and R. Takagi, Phys. Rev. Lett. 126, 110403,
DOI: doi.org/10.1103/PhysRevLett.126.110403

The gist of it

It is well established that several features of quantum mechanical systems with no classical counterparts can be exploited as resources in practical applications, such as communication, computation, sensing and cryptography. It is then of paramount importance to rigorously quantify such an advantage, especially in relation to some explicit task that one might want to perform in a realistic scenario. In these two papers, we study the (generalized) robustness as a measure of a very large family of generic quantum resources, and its relation with a key task in quantum information: quantum channel discrimination. In particular, we prove that the robustness precisely quantifies the maximum advantage given by a resourceful state with respect to any free one, when used as a probe to determine which physical evolution it underwent. Our framework can be applied well beyond standard finite-dimensional quantum theory, and in particular, to all finite- and infinite-dimensional general probabilistic theories, i.e., generalizations of quantum mechanics itself. This is interesting both from a fundamental and practical perspective, as many resources needed for quantum technologies, e.g. nonclassicality and non-Gaussianity, are peculiar of systems with an associated infinite-dimensional Hilbert space.

Picture of the Publication

Parallel selective nuclear-spin addressing for fast high-fidelity quantum gates, B. Tratzmiller, J. F. Haase, Z. Wang, and M. B. Plenio, Phys. Rev. A 103, 012607
DOI: doi.org/10.1103/PhysRevA.103.012607

The gist of it

Due to their long coherence times, nuclear spins have gained considerable attention as physical qubits. Their interaction can be mediated by nitrogen vacancy (NV) centers in diamond. In this work we generalize PulsePol, a pulse sequence developed in the Institute of Theoretical Physics to achieve robust polarization transfer from NV centers to nuclear spins, to a sequence that is resonant to two frequencies simultaneously, allowing to perform gates between two nuclear spins.

This approach results in efficient entangling gates that, compared to standard techniques, reduce the gate time by more than 50% when the gate time is limited by off-resonant coupling to other spins, and by up to 22% when the gate time is limited by small electron-nuclear coupling.

 

Precise Spectroscopy of High-Frequency Oscillating Fields with a Single-Qubit Sensor, Y. Chu, P. Yang, M. Gong, M. Yu, B. Yu, M. B. Plenio, A. Retzker, and J. Cai, Phys. Rev. Applied 15, 014031
DOI: doi.org/10.1103/PhysRevApplied.15.014031

Most Recent Papers

Framework for resource quantification in infinite-dimensional general probabilistic theories, Phys. Rev. A 103, 032424

Operational Quantification of Continuous-Variable Quantum Resources, Phys. Rev. Lett. 126, 110403

Parallel selective nuclear-spin addressing for fast high-fidelity quantum gates, Phys. Rev. A 103, 012607

 

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