Quantum Optics Group (LMU) - Quantum Many Body Systems Division (MPQ)

We observed spatially ordered structures of collective excitations in a gas of laser excited Rydberg atoms. The comparison of the measured excitation dynamics to a theoretical model developed by our colleagues at the MPIPKS in Dresden provides evidence for coherence between the different excitation patterns. Nature 491, 87-91 (2012), Press Release MPQ (english, deutsch)

We congratulate Simon Braun and the whole team on the Poster Prize of the AMO division of the French Physical Society (PAMO) award at the ICAP 2012 for the poster on "Negative absolute temperature for motional degrees of freedom" (ArXiv:1211.0545


We detected a Higgs-type excitations in a low-dimensional system of ultracold atoms at the transition between different phases of matter. The work was done in close collaboration with colleagues from Harvard and Caltech. Nature 487, 454-458 (2012), Press Release MPQ (english, deusch), Additional Media

In a collaboration with theoretical physicists from Potsdam, Brisbane, Jülich and the LMU, we have investigated the relaxation of a bosonic density wave towards equilibrium. Using an optical superlattice, we were able to prepare the initial state with high fidelity and to follow the dynamics in terms of quasi-local densities, currents and coherences. Nature Physics 8, 325 (2012). Cover Story. (Additional Media)

By means of two perpendicular superlattices we have realized a three-dimensional array of independent plaquettes where we studied the spin physics of four site localized bosonic particles. We were able to observe valence bond oscillations as well as to create and characterize two resonating valence bond states with s- and d-wave symmetry.These two states constitute a minimum basis of a topologically protected qubit. Phys. Rev. Lett. 108, 205301 (2012).

We studied the expansion of an initially confined fermionic quantum gas in the lowest band of a homogeneous optical lattice and observed a crossover from ballistic transport for non-interacting atoms to an almost bimodal dynamics in the interacting case. Nature physics 8, 213  (Additional Material)

We observed how correlations propagate across a one-dimensional bosonic Mott insulator after the system has been set out of equilibrium. Our measurements show that the dynamics is bounded by a maximum velocity, reminding of the light cone that separates time-like from space-like intervals in the theory of special relativity. Nature 481, 484 (2012). Press release MPQ (deueng). Additional Media.

Prof. Christophe Salomon, laureate of Gay-Lussac-Humboldt prize 2011, has joined our group on January 2012 as a guest scientist. 
Christophe Salomon is research director at C.N.R.S.- Laboratoire Kastler Brossel at the  Ecole Normale Supérieure in Paris. There he leads a group on Ultra cold fermi gases, which has been responsible for seminal advancements in the field.  During his stay in Munich he will work in the field of ultracold quantum gases at MPQ and LMU.