Hannover 2013 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 40: Quantum gases: Optical lattices II
Q 40.1: Vortrag
Mittwoch, 20. März 2013, 14:00–14:15, A 310
Expansion dynamics of interacting bosons in homogeneous lattices in one and two dimensions — •Jens Philipp Ronzheimer1,2, Michael Schreiber1,2, Simon Braun1,2, Sean S. Hodgman1,2, Stephan Langer2,3, Ian P. McCulloch4, Fabian Heidrich-Meisner2,5, Immanuel Bloch1,2, and Ulrich Schneider1,2 — 1LMU München — 2MPQ Garching — 3University of Pittsburgh, USA — 4University of Queensland, Brisbane, Australia — 5Universität Erlangen-Nürnberg, Erlangen
We study out-of-equilibrium dynamics and transport properties of interacting many-body systems using ultracold atoms in optical lattices. Specifically, we investigate the expansion dynamics of initially localized bosons in homogeneous 1D and 2D Hubbard systems. We find that the fastest, ballistic expansions occur in the integrable limits of the system. In 1D, these are both the non-interacting case as well as the hard-core regime, i.e. the strongly-interacting limits in the absence of doubly or higher occupancies. Any deviation from these limits, either through finite interactions or the admixture of double occupancies in the initial state for strong interactions, significantly slows down the expansion. In 2D, the strongly interacting limit is fundamentally different: Here, the system expands ballistically only in the non-interacting case, while all interactions lead to strongly diffusive behavior. By controlling the tunneling along individual lattice axes, we can gradually change the dimensionality of the system from 1D to 2D. In the strongly interacting case, we observe how the initially ballistic dynamics in a 1D system turn diffusive when additional degrees of freedom become available.