Real-time dynamics of lattice bosons from nonequilibrium dynamical mean-field theory
17.10.2014 at 09:00
We extend the bosonic dynamical mean-field formalism to nonequilibrium situations and test it in combination with a Nambu real-time strong coupling perturbative impurity solver . The formalism correctly describes the Mott insulating, superfluid and normal phases, and captures damping and thermalization at finite temperatures, in contrast to other real-time approaches.
As a first application we study bosonic cold-atoms in an optical lattice using the Bose-Hubbard model. We drive the system out of equilibrium by quenching the interaction, mimicking the seminal cold-atom experiment of Greiner et al. . Starting from both the normal and superfluid phase, we map out non-equilibrium phase diagrams which identify the different dynamical regimes. A multitude of behaviors are observed, including rapid thermalization and trapping in meta-stable normal and superfluid states. Depending on parameters, the condensate displays long lived or strongly damped amplitude oscillations.
Nonequilibrium bosonic dynamical mean-field theory can be straightforwardly extended to enable the study of the nonequilibrium properties of bosonic multi-component systems  and Bose-Fermi mixtures .
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