Wednesday, December 5, 2012

1212.0223 (N. Sedlmayr et al.)

When is a bath a bath? Relaxation dynamics and thermalization in a
fermionic chain
   [PDF]

N. Sedlmayr, J. Ren, F. Gebhard, J. Sirker
We study thermalization in a one-dimensional quantum system consisting of a non-interacting 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.
View original: http://arxiv.org/abs/1212.0223

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