Time evolution and steady states of dissipative quantum many-body systems

Abstract

We investigate a dissipative Ising model that exhibits the Ising symmetry via a variational approach. In the non-equilibrium steady state phase diagram, we find a first order and a second order transition meeting at a tricritical point. An experimental realization via Rydberg dressing is suggested. In the second part, we use the variational approach to calculate the time evolution of a dissipative Ising model that shows a first order liquid gas transition. As an extension of the variational product state, classical fluctuations are included. In the last part, we investigate a system where a Nitrogen-vacancy center in diamond is coupled to many carbon nuclei. We show that close to the ground state level anti crossing condition, the NV center and the nuclei can exchange polarization laying the basis for spin bath polarization.