Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 37: Matter At Low Temperature: Quantum Liquids, Bose-Einstein Condensates, Ultra-cold Atoms, ... 2

TT 37.8: Talk

Thursday, March 29, 2012, 11:30–11:45, H 3005

Damping of Bloch Oscillations in the Hubbard Model — •Martin Eckstein¹ and Philipp Werner² — ¹Max Planck Research Department for Structural Dynamics, University of Hamburg, Centre for Free Electron Laser Science, Hamburg, Germany — ²Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland

Using nonequilibrium dynamical mean-field theory (DMFT), we study the isolated Hubbard model in a static electric field in the limit of weak interactions. Linear response behavior is established at long times, but only if the interaction exceeds a critical value, below which the system exhibits an ac-type response with Bloch oscillations [1]. The transition from ac to dc response is defined in terms of the universal long-time behavior of the system, which does not depend on the initial condition. In order to understand whether these phenomena can be observed in experiments with ultracold gases, one has to estimate the importance of the inhomogeneous confining trap. This is done within a realspace DMFT approach.
M. Eckstein and Ph. Werner, Phys. Rev. Lett. 107, 186406 (2011).