## Ultracold bosons on optical lattices: Ideal testbed to study nonequilibrium dynamics

**Dr Lev Vidmar**, Ludwig-Maximilians-Universität München

23.05.2014, 12:15, room 357, Bankowa 14

When initially a closed quantum system in prepared in a state which is not an eigenstate of the system, it undergoes a unitary time-evolution and relaxes to some steady state. Investigation of the steady state properties of fundamental models represents a very active research topic of many-body quantum physics. In generic (non-integrable) systems, the long-time values of (local) observables eventually approach expectation values of a thermal ensemble where only a few quantities, like the energy density, characterize the state. The framework to study these properties is the so-called eigenstate thermalization hypothesis, which, however, does not represent the necessary condition to observe thermal properties. In contrast, thermal ensembles usually fail to describe integrable systems, where the dynamics is constrained by the set of integrals of motion. Beside these scenarios, the system may first evolve into some transient metastable states, which feature nontrivial properties such as quasi-condensation of bosons in a co-moving frame. In my talk, I will show that all these features mentioned above can be studied experimentally with ultracold bosons on optical lattices using the same initial state, i.e., a product of local Fock states with one boson per site. While most of the results will be discussed using exact numerical methods on one-dimensional lattice systems (exact diagonalization and density-matrix renormalization group), these results open a new way towards studying the interplay of dimensionality, interactions and different particle species in a well-controlled nonequilibrium environment.