Closed and Open System Dynamics in a Fermionic Chain with a   Microscopically Specified Bath: Relaxation and Thermalization
  We study thermalization in a one-dimensional quantum system consisting of a noninteracting fermionic chain with each site of the chain coupled to an additional bath site. Using a density matrix renormalization group algorithm we investigate the time evolution of observables in the chain after a quantum quench. For low densities we show that the intermediate time dynamics can be quantitatively described by a system of coupled equations of motion. For higher densities our numerical results show a prethermalization for local observables at intermediate times and a full thermalization to the grand canonical ensemble at long times. For the case of a weak bath-chain coupling we find, in particular, a Fermi momentum distribution in the chain in equilibrium in spite of the seemingly oversimplified bath in our model. 
N. Sedlmayr, J. Ren, F. Gebhard, J. Sirker
cond-mat.stat-mech cond-mat.str-el quant-ph