Effective temperature from fluctuation-dissipation theorem in systems with bipartite eigenmode entanglement

BORTOLIN, TOMÁS SEBASTIÁN; IUCCI, CARLOS ANÍBAL

Trieste

Congreso; School on Non-linear Dynamics, Dynamical Transitions and Instabilities in Classical and Quantum Systems; 2014

ICTP

In thermal equilibrium, the fluctuation-dissipation theorem relates the linear response and correlation functions in a model and observable independent fashion. Out of equilibrium, these relations still hold if the equilibrium temperature is replaced with a observable and frequency-dependent parameter (effective temperature). When the system achieves a long time thermal state all of these effective temperatures should be equal and constant. Following this approach, we examine the long time after the quench dynamics of a system with bipartite entanglement, in which observable asymptotic values are compatible with the ones obtained in a Gibbs ensemble. The appearance of  distinct effective temperatures discards thermalization.