­­Theoretical Quantum Gases

-theory of fundamental physics and chemistry in ultracold clouds-



We explore universal phenomena in few-body physics and quantum reaction dynamics in chemistry. For this, we theoretically investigate collision processes between several particles in the ultracold regime.  This is done by solving quantum-mechanical few-body equations, for instance, the time-independent Schrödinger equation on adiabatic few-body potentials. The obtained information, such as the three-body loss rate L3 and the three-body correlation paramter g3, enables us to build up fundamental (effective) Hamiltonians for studying many-body physics.


Our research interest

  • Universal few-body physics
  • Ultracold chemical reactions
  • From few-body to many-body Physics

Ongoing research projects


Full-dimensional quantum calculation on ultracold triatomic reactions

In the ultracold regime, the quantum mechamics play a crucial in chemical reactions and the full-dimensional spatial movement of the reacting particles can entangle strongly with the rotation of their spins. We are currently working with a quantum treatment, taking into account all these spatial and spin degrees of freedom, to study the state-to-state reaction dynamics of the three-body recombination process in ultracold Rubidium atoms. This project is closely connected to the experiment in our BaRbIE laboratory. Please click here to reach the experimental page.


Prediction of the value of Efimovian three-body parameters in ultracold atoms

When a three-body system encouters resonant two-body interactions, there will be an infinite series of trimer states appear with a geometrically distributed spectrum, which is called the Efimov effect. This geometrical spectrum itself is universal but need to be fixed by a few three-body parameters. We are currently working on calculating these Efimovian parameters and testing whether additional universalities even apply for their values.


The Team


Prof. Dr. Johannes Hecker Denschlag


Dr. Jinglun Li



Jose P D'Incao

Assistant Research Professor
Group of Ultracold Few-Body Physics, JILA, Department of Physics, University of Colorado.

Paul S. Julienne

JQI Emeritus Fellow
Joint Quantum Institute (JQI), University of Maryland and NIST.

Eberhard Tiemann

Emeritus Professor
Institut für Quantenoptik, Leibniz Universität Hannover.