Im Neuenheimer Feld 226
Tel: 06221/ 54 19471
Fax: 06221/ 54 19545
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
|New flavor of universal three-body physics discovered||10.10.2016|
In our studies we used an ultracold mixture of Li and Cs atoms to investigate the heteronuclear Efimov scenario. In this scenario, three particles, for our system one Li atom and two Cs atoms, bind together in a bound state even though none of the individual pairs can be bound (analogous to Borromean rings). In the experiments and theory we replaced the unbound Cs pair with a bound one. To our surprise, the resulting Efimov scenario was independent of molecular forces that govern chemical binding of atoms into molecules: the binding of the three atoms was purely quantum-mechanical and the three-body system became truly universal. In this regime it would not matter if one used atoms or nucleons with the same mass ratio and interactions. Furthermore, our experiments showed that the Efimov effect itself is severely modified by the same change of the fundamental nature of the Cs-Cs bond.
The peculiar nature of Efimov physics is illustrated in the figure. It shows the probability density distribution of the Li atom in a CsCsLi Efimov molecule. The two red balls along the central symmetry line indicate the two Cs atoms, which are separated by about 8 nm. In comparison, a typical chemist's molecule, such as CsCs, LiCs or LiCsCs, would have a spatial extent smaller than 1 nm, which was roughly the size of the dark spot between the two Cs atoms. Figure courtesy of Yujun Wang, Kansas State University.
Heteronuclear Efimov Scenario with Positive Intraspecies Scattering Length, Phys. Rev. Lett. 117, 153201 (2016), or see our full list of publications
|Signing ceremony of a Memorandum of Understanding for a Joint German-Sino Institute for Advanced Quantum Science||03.10.2016|
For more information:
|Density matrix reconstruction of three-level atoms via Rydberg electromagnetically induced transparency published in J. Phys. B: At., Mol. Opt. Phys.!||22.07.2016|
Our method gives a simple explanation to the counter-intuitive features observed in the spectra and provides the optical susceptibility and the Rydberg density as a function of spatial position, as well as the spatial profile of Rabi frequencies of the coupling laser. These results help elucidate the interplay of matter and light degrees of freedom in three-level media and will facilitate new studies of many-body effects in optically driven Rydberg gases.
Density matrix reconstruction of three-level atoms via Rydberg electromagnetically induced transparency, J. Phys. B: At., Mol. Opt. Phys. 49, 164002 (2016), or see our full list of publications