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

Autor(es)

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

Afiliação do(s) autor(es)

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

• Tipo de documento: Artigo Científico
• Fonte: European Physical Journal-Special Topics; v. 227, n. 3-4, p. 301-311, SEP 2018.
• Citações Web of Science: 1

Resumo

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)

• Processo FAPESP: 09/53826-8 - Dinâmica de cadeias quânticas de spin acopladas a graus de liberdade externos
• Beneficiário: Alexis Omar García Rodríguez
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 17/07016-0 - 14th Granada Seminar on Computational and Statitical Physics
• Beneficiário: Guillermo Gerardo Cabrera Oyarzun
• Modalidade de apoio: Auxílio à Pesquisa - Reunião - Exterior