Erlangen 2018 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 11: Cold atoms III - optical lattices (joint session A/Q)

Q 11.6: Vortrag

Montag, 5. März 2018, 15:15–15:30, K 0.011

Metastability and avalanche dynamics in strongly-correlated gases with long-range interactions — •Nishant Dogra, Lorenz Hruby, Manuele Landini, Katrin Kröger, Tobias Donner, and Tilman Esslinger — Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland

We experimentally study the stability of a bosonic Mott-insulator against the formation of a density wave induced by long-range interactions. The Mott-insulator is created in a quantum degenerate gas of 87-Rubidium atoms, trapped in a three-dimensional optical lattice. The gas is located inside and globally coupled to an optical cavity. This causes interactions of global range, mediated by photons dispersively scattered between a transverse lattice and the cavity. The scattering comes with an atomic density modulation, which is measured by the photon flux leaking from the cavity. We initialize the system in a Mott-insulating state and then quench the global coupling strength. We observe that the system falls into either of two distinct final states. One is characterized by low photon flux, signaling a Mott insulator, and the other is characterized by high photon flux, which we associate with a density wave. Ramping the global coupling slowly, we observe a hysteresis loop between the two states. From the increasing photon flux monitored during the switching process, we find that several thousand atoms tunnel to a neighboring site on the time scale of the single particle dynamics which can be understood as an avalanche tunnelling process in the Mott-insulating region.