We consider a quantum quench in a noninteracting fermionic one-dimensional field theory. The system of size L is initially prepared into two halves L ([-L/2,0]) and R ([0,L/2]), each of them thermalized at two different temperatures TL and TR, respectively. At a given time, the two halves are joined together by a local coupling and the whole system is left to evolve unitarily. For an infinitely extended system (L→), we show that the time evolution of the particle and energy densities is well described via a hydrodynamic approach which allows us to evaluate the correspondent stationary currents. We show, in such a case, that the two-point correlation functions are deduced, at large times, from a simple nonequilibrium steady state. Otherwise, whenever the boundary conditions are retained (in a properly defined thermodynamic limit), any current is suppressed at large times, and the stationary state is described by a generalized Gibbs ensemble, which is diagonal and depends only on the post-quench mode occupation.

Quantum quench from a thermal tensor state: Boundary effects and generalized Gibbs ensemble / Collura, Mario; Karevski, Dragi. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 89:21(2014), pp. 1-12. [10.1103/PhysRevB.89.214308]

Quantum quench from a thermal tensor state: Boundary effects and generalized Gibbs ensemble

Collura, Mario;
2014

Abstract

We consider a quantum quench in a noninteracting fermionic one-dimensional field theory. The system of size L is initially prepared into two halves L ([-L/2,0]) and R ([0,L/2]), each of them thermalized at two different temperatures TL and TR, respectively. At a given time, the two halves are joined together by a local coupling and the whole system is left to evolve unitarily. For an infinitely extended system (L→), we show that the time evolution of the particle and energy densities is well described via a hydrodynamic approach which allows us to evaluate the correspondent stationary currents. We show, in such a case, that the two-point correlation functions are deduced, at large times, from a simple nonequilibrium steady state. Otherwise, whenever the boundary conditions are retained (in a properly defined thermodynamic limit), any current is suppressed at large times, and the stationary state is described by a generalized Gibbs ensemble, which is diagonal and depends only on the post-quench mode occupation.
89
21
1
12
214308
https://arxiv.org/abs/1402.1944
Collura, Mario; Karevski, Dragi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/103448
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