Thermalization of interacting fermions and delocalization in Fock space.

We investigate the onset of "eigenstate thermalization" and the crossover to ergodicity in a system of one-dimensional fermions with increasing interaction. We analyze the fluctuations in the expectation values of most relevant few-body operators with respect to eigenstates. It turns out that these are intimately related to the inverse participation ratio of eigenstates displayed in the operator eigenbasis.

Localized phase structures growing out of quantum fluctuations in a quench of tunnel-coupled atomic condensates.

We investigate the relative phase between two weakly interacting 1D condensates of bosonic atoms after suddenly switching on the tunnel coupling. The following phase dynamics is governed by the quantum sine-Gordon equation. In the semiclassical limit of weak interactions, we observe the parametric amplification of quantum fluctuations leading to the formation of breathers with a finite lifetime.

Universal dephasing in a chiral 1D interacting fermion system.

We consider dephasing by interactions in a one-dimensional chiral fermion system (e.g., a quantum Hall edge state).

Self-induced oscillations in an optomechanical system driven by bolometric backaction.

We have explored the nonlinear dynamics of an optomechanical system consisting of an illuminated Fabry-Perot cavity, one of whose end mirrors is attached to a vibrating cantilever. The backaction induced by the bolometric light force produces negative damping such that the system enters a regime of nonlinear oscillations. We study the ensuing attractor diagram describing the nonlinear dynamics.