Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 19: Quantum Gases: Miscellaneous
Q 19.1: Vortrag
Dienstag, 15. März 2011, 10:30–11:00, HÜL 386
Interacting ultracold bosons in optical lattices: Scattering and decoherence — •Hannah Venzl1, Stefan Hunn1, Scott Sanders1, Tobias Zech1, Lewin Stein1,2, Florian Mintert3, Moritz Hiller1, and Andreas Buchleitner1 — 1Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg — 2Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin — 3Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs-Universität Freiburg, Albertstraße 19, 79104 Freiburg
Ultracold bosons in optical lattices provide a versatile testing ground to investigate complex quantum phenomena. In this talk, we address the implications of the inter-particle interactions from two complementary perspectives: On the one hand, we devise a matter-wave scattering approach and probe the system via the inelastic scattering cross section. Within the first-order Born approximation, we reveal unambigous traces of the Mott-insulator to superfluid phase transition. Beyond these ground-state properties, also the excitation spectrum of a BEC is probed. In the parameter regime where the interactions induce chaotic spectral statistics, we observe universal Ericson fluctuations with characteristic features rooted in the underlying mean-field equations.
On the other hand, we investigate how the spectral properties are reflected in the system’s dynamics: We find that the interactions lead to decoherence, which results in a fast and irreversible decay of Bloch oscillations, and obtain the corresponding decay rate from the local density of states.