Berlin 2014 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 31: Ultracold atoms, ions and BEC III (with A)

Q 31.4: Vortrag

Mittwoch, 19. März 2014, 15:00–15:15, UDL HS3038

Bose-Einstein condensation of ultra-cold atoms in a frustrated, triangular optical lattice II. — Robert Höppner¹, Julian Struck¹, Malte Weinberg¹, Christoph Ölschläger¹, Patrick Windpassinger^1,3, Juliette Simonet¹, Klaus Sengstock¹, Ludwig Mathey¹, •Philipp Hauke⁵, André Eckardt⁴, and Maciej Lewenstein² — ¹ILP/ZOQ (Hamburg) — ²ICFO/ICREA — ³Uni Mainz — ⁴MPIPKS — ⁵Uni Innsbruck

We study the condensation in frustrated, triangular optical lattices, with emphasis on numerical simulations. We implement the system using a semiclassical version of the Bose-Hubbard model and generate samples of the grand-canonical ensemble using Metropolis Monte-Carlo from which we then calculate the observables. As discussed in Ref. [1], periodic driving of the optical lattice potential generates an effective tunneling energy that becomes complex, thereby creating an artificial gauge-field that acts as a control field of the chiral order that emerges in this system. In analogy to the experimental study, we numerically determine the magnetization curves of the chiral order parameter as function of the artificial gauge field. We demonstrate that the experimentally realized ensemble is not in equilibrium, showing hysteric-like behavior. Beyond the equilibrium system, we therefore also comment on the quench dynamics from the positive tunneling (ferromagnet-like phase) to the negative tunneling, fully frustrated phase.

[1] "Engineering Ising-XY spin-models in a triangular lattice using tunable artificial gauge fields." Nature Physics (2013)