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TT: Fachverband Tiefe Temperaturen

TT 23: Correlated Electrons: (General) Theory

TT 23.9: Vortrag

Mittwoch, 27. Februar 2008, 16:15–16:30, H 0104

Real-time evolution of the nonequilibrium Hubbard model — •Michael Möckel and Stefan Kehrein — LMU München, Department für Physik und Arnold Sommerfeld Center for Theoretical Physics, Theresienstraße 37, 80333 München

Recent experiments with cold atomic gases loaded onto optical lattices have opened up a new line of research into nonequilibrium properties of closed quantum systems. Motivated by these results we study the Hubbard model in infinite dimensions for a weak two-particle interaction U Θ(t) which is switched on instantaneously in time. We address the question of its real-time evolution by means of the flow equation technique and calculate the time-dependent momentum distribution function. After an initial buildup of a correlated distribution on a time scale set by U⁻¹ a nonequilibrium transient state extends on a long time scale proportional to U⁻⁴. It resembles an interacting Fermi liquid at zero temperature but its quasiparticle residuum mismatches the value for the correlated equilibrium state.