Hannover 2016 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 70: Quantum Gases: Bosons VI

Q 70.3: Talk

Friday, March 4, 2016, 15:00–15:15, f342

Observation of symmetry-broken momentum distributions: matter-wave diffraction during time-of-flight expansion — •Christoph Ölschläger, Malte Weinberg, Ole Jürgensen, Dirk-Sören Lühmann, Juliette Simonet, and Klaus Sengstock — Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg

The information about quantum gas systems is still commonly inferred from time-of-flight measurements.

Here, we demonstrate that interaction during the time-of-flight expansion can strongly alter the measurement of the initial atomic momentum distribution. We discuss the observation of symmetry-broken momentum distributions for bosonic mixtures in state-dependent honeycomb lattices due to scattering processes within the first milliseconds of the expansion time.

These findings play an inevitable role in a broad range of systems, including state-dependent lattices and superlattices, where the lattice symmetry does not cancel the influence of the scattering processes on the interference pattern. In addition, the interactions during a free expansion can indeed be used as an interferometric probe to reveal novel quantum phases, such as supersolids.