Hannover 2016 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 27: Poster: Quantum Optics and Photonics II
Q 27.27: Poster
Dienstag, 1. März 2016, 16:30–19:00, Empore Lichthof
Many-body correlations in the spectrum of two-dimensional Bose-Hubbard models — •Darius Hoffmann1, David Fischer1, and Sandro Wimberger1,2,3 — 1Institut für Theoretische Physik, Universität Heidelberg, 69120 Heidelberg, Germany — 2Dipartimento di Fisica e Scienze della Terra, Università di Parma, Via G. P. Usberti 7/a, 43124 Parma, Italy — 3INFN, Sezione di Milano Bicocca, Gruppo Collegato di Parma, Italy
We present detailed results on two-dimensional Bose Hubbard models of finite sizes. Such systems are relevant for high-fidelity experiments with ultracold quantum gases loaded into periodic lattice structures. Our analysis is based on the spectral characterization of two-dimensional lattices with a variety of bonds and different boundary conditions, representing different lattice geometries. In the limit of maximally linked lattice clusters regular motion prevails, which is understood by the applicability of mean-field methods in these cases. On the other hand, in standard lattices with less bonds, such as realized in typical experiments, quantum chaotic behavior is found for a wide range of parameters. Our analysis includes measures of spectral complexity from Random-Matrix Theory (RMT), i.e. nearest neighbor (gap) statistics and long-range spectral correlations, but also a new measure recently introduced in the context of many-body localization in isolated quantum systems. Implications for the temporal evolution of two-dimensional interacting lattices gases are discussed as well.