Quantum dynamics of atomic and molecular systems

Our group studies atomic and molecular quantum systems with respect to their interactions on different levels of complexity. Of special importance is the application and extension of modern methods for the manipulation and quantum control to many-body quantum systems, in particular using coherent light. The systems under investigation range from highly excited Rydberg atoms over atomic and molecular quantum gases to molecular aggregates. The group develops technologies for trapping and cooling of neutral atoms as well as quantum-state sensitive diagnostics.

Latest news from the lab

Scattering of two heavy Fermi polarons - resonances and quasibound states: paper published in PRA17.12.2020
Eleonora Lippi

Our paper on the " Scattering of two heavy Fermi polarons: Resonances and quasibound states” got published this month in PRA! We theoretically investigate the scattering properties and compute the scattering phase shifts and scattering lengths between two heavy impurities in an ideal Fermi gas at zero temperature. We find that impurities strongly and attractively interacting with the medium exhibit resonances in the induced scattering with a sign change of the induced scattering length and even strong repulsion.

T. Enss et al., Scattering of two heavy Fermi polarons: Resonances and quasibound states , PhysRevA, 102.063321 (2020) , or see our full list of publications
Fermions Meet Two Bosons - the Heteronuclear Efimov Effect Revisited: paper published in Braz. J. Phys.09.11.2020
Eleonora Lippi

Our paper on the "Fermions Meet Two Bosons—the Heteronuclear Efimov Effect Revisited" got published in Braz. J. Phys., in a special issue for Prof. Mahir S. Hussein! In this paper we theoretically investigate two limiting cases of the Efimov scenario, first, in vacuum, and second, in the presence of a Fermi Sea, focusing on the specific case of two heavy bosons and a light fermion. While the first case reproduces the well-known features of the Efimov effect, the second case provides novel insights serving as a precursor to understand effective interactions of Fermi polarons, i.e., strongly correlated impurities in a Fermi sea.

B. Tran et al., Fermions Meet Two Bosons—the Heteronuclear Efimov Effect Revisited, Braz. J. Phys. (2020), https://doi.org/10.1007/s13538-020-00811-5, or see our full list of publications
Successful second funding period bid of IsoQuant (CRC 1225) 01.06.2020
Eleonora Lippi

Our collaborative research centre (CRC 1225) studying “Isolated Quantum Systems and Universality in Extreme Conditions” has been granted and will continue its work in the second funding period, from July 2020 to 2024! Our group will continue to participate in the collaboration to the project A05 “Dynamics of tunable disordered many-body spin systems” and C03 “Fermi-Bose mixtures with large mass ratio”. Congratulation to everybody!

For more information:
Website: IsoQuant (CRC1225)

For more highlights see our news page

Research topics

Mixtures of ultracold atoms and molecules

In this experiment we use a mixture of two different alkali metals: cesium and lithium. This gives us the possbility to form ultracold LiCs dimers. These molecules have an extremely large electric dipole moment which promises many new experiments. For example, the molecules can be orientated in an external electric field.

Strongly-correlated Rydberg quantum gases

Rydberg atoms are atoms in highly excited electronic states. These atoms are very sensitive to external fields and experience extremely strong interactions with other Rydberg atoms. This gives us a model system for studying strongly-correlated quantum systems that is highly controllable and completely governed by interatomic interactions.

Hybrid ion atom trap for cold chemistry experiments

Interactions between ions and neutrals play an important role in all kind of chemical reactions. In order to gain a full understanding of these systems we are trying to observe reactions at ultra-low temperatures. In this regime the reaction dynamics are no longer concealed by the thermal movement of the particles.

Rydberg physics with ultracold two-electron systems

We are setting up an experiment to study the physics of two-electron Rydberg atoms using a quantum gas of ultracold strontium. The experiment is located at the University of Science and Technology of China (USTC Shanghai Institute for Advanced Studies). First studies will be aiming to explore many-body effects induced by the long-range interactions between highly excited strontium Rydberg atoms, using the inner electron to control the atom's motion and to detect single Rydberg atoms.