Interaction-disorder competition in a spin system evaluated by the Loschmidt Echo

PABLO RENÉ ZANGARA; PATRICIA R. LEVSTEIN; HORACIO MIGUEL PASTAWSKI

Trieste

Conferencia; Conference on Frustration, Disorder and Localization: Statics and Dynamics; 2015

The Abdus Salam International Centre for Theoretical Physics

The interplay between interactions and disorder in closed quantum many-body systems is nowadays relevant for thermalization phenomena. We address this competition in an infinite-temperature spin system, by means of the Loschmidt Echo (LE), which is based on a partial time reversal procedure. This quantity has been formerly employed to connect quantum and classical chaos, and here we use it to filter out an irrelevant part of the Hamiltonian. The scaling of the LE decay rates is analyzed as function of the interactions and disorder strengths. The natural bound for these rates is found to be the time-scale of the Survival Probability under the reversed (unperturbed) Hamiltonian. Moreover, the strategy enables a phase diagram that shows the regions of ergodic and non-ergodic behavior of the polarization under the echo dynamics.