Non-ergodic states induced by impurity levels in quantum spin chains

Author(s)

Garcia Rodriguez, A. O. ^[1] ; Cabrera, G. G. ^[1]

Affiliation

^[1] Univ Estadual Campinas, UNICAMP, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil

• Document type: Journal article
• Source: European Physical Journal-Special Topics; v. 227, n. 3-4, p. 301-311, SEP 2018.
• Web of Science Citations: 1

Abstract

The semi-infinite XY spin chain with an impurity at the boundary has been chosen as a prototype of interacting many-body systems to test for non-ergodic behavior. The model is exactly solvable in analytic way in the thermodynamic limit, where energy eigenstates and the spectrum are obtained in closed form. In addition of a continuous band, localized states may split off from the continuum, for some values of the impurity parameters. In the next step, after the preparation of an arbitrary non-equilibrium state, we observe the time evolution of the site magnetization. Relaxation properties are described by the long-time behavior, which is estimated using the stationary phase method. Absence of localized states defines an ergodic region in parameter space, where the system relaxes to a homogeneous magnetization. Out of this region, impurity levels split from the band, and localization phenomena may lead to non-ergodicity. (AU)

• FAPESP's process: 17/07016-0 - 14th Granada Seminar on Computational and Statitical Physics
• Grantee: Guillermo Gerardo Cabrera Oyarzun
• Support Opportunities: Research Grants - Meeting - Abroad