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

News 2011

We have realized a strong effective magnetic field in an optical lattice, which should allow one to investigate fractional quantum Hall physics and beyond with ultracold atoms. The Aharonov-Bohm phase is simulated using Raman-assisted atom tunneling. We observe that the effective magnetic field leads to a frustrated ground state and to quantum cyclotron orbits. Phys. Rev. Lett. 107, 255301 (2011). Viewpoint Physics.

We succeeded in directly imaging quantum fluctuations that show up as particle-hole pairs in a bosonic Mott insulator. The pairwise appearance of the fluctuations also leads to a non-local order that we probed in the experiment. Science 334, 200 (2011). Press release MPQ (deu, eng). MPG (deu). Additional Media

Coherent light scattering from only a few hundred atoms in atomic Mott insulator yields a far-field diffraction pattern. We used this technique to detect one-dimensional antiferromagnetic order via additional diffraction peaks. Phys. Rev. Lett. 106, 215301 (2011). Viewpoint Physics.



With lattice shaking, we are able to control correlated tunneling and superexchange interactions in isolated double well potentials. This technique opens the possibility to simulate an arbitrary XXZ spin model. Phys. Rev. Lett. 107, 210405 (2011)

We addressed and changed the spin of individual atoms in an optical lattice with laser light and arranged the atoms in arbitrary patterns. These results are an important step towards large scale quantum computing and for quantum simulation of condensed matter systems [Nature 471, 319 (2011)]. Press release MPQ (deu, eng), MPG (deu). Nature Physics News & Views, Additional media.

We have experimentally realized few-body impurity systems consisting of a single fermion and a miniature Bose-Einstein condensate. Using quantum phase revival spectroscopy, we revealed how the presence of the interacting impurity fermion modifies the interactions among the bosons. Phys. Rev. Lett 106, 115305 (2011)

We have studied the non-equilibrium dynamics in tunnel coupled 1D Bose liquids, extending the famous Landau-Zener problem to a low-dimensional many-body setting. Most strikingly, we found a drastic breakdown of the adiabatic transfer between the Bose liquids upon Landau-Zener sweeps in the highest-energy states [Nature Physics 7, 61 (2011)]. Press release MPQ (deu, eng).