Nonequilibrium symmetry-protected topological order: emergence of semilocal Gibbs ensembles

Fagotti, Maurizio (author), Marić, Vanja (author), Zadnik, Lenart (author)

We consider nonequilibrium time evolution in quantum spin chains after a global quench. Usually a nonequilibrium quantum many-body system locally relaxes to a (generalized) Gibbs ensemble built from conserved operators with quasilocal densities. Here we exhibit explicit examples of local Hamiltonians that possess conservation laws with densities that are not quasilocal but act as such in the symmetry-restricted space where time evolution occurs. Because of them, the stationary state emerging at infinite time can exhibit exceptional features. We focus on a specific example with a spin-flip symmetry, which is the commonest global symmetry encountered in spin-1/2 chains. Among the exceptional properties, we find that, at late times, the excess of entropy of a spin block triggered by a local perturbation in the initial state grows logarithmically with the subsystem's length. We establish a connection with symmetry-protected topological order in equilibrium at zero temperature and study the melting of the order induced either by a (symmetry-breaking) rotation of the initial state or by an increase of the temperature.

• Language: English
• Keywords: statistical physics, nonequilibrium statistical mechanics
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication version: Author Accepted Manuscript
• Publication date: 11.03.2024
• Year: 2024
• Number of pages: Str. 115117-1-115117-37
• Numbering: Vol. 109, iss. 11
• PID: 20.500.12556/RUL-154971
• UDC: 536.9
• ISSN on article: 2469-9950
• DOI: 10.1103/PhysRevB.109.115117
• COBISS.SI-ID: 188529667
• Publication date in RUL: 12.03.2024

Record is a part of a journal

• Title: Physical review
• Publisher: American Physical Society
• ISSN: 2469-9950
• COBISS.SI-ID: 2997348

Secondary language

• Language: Slovenian
• Keywords: statistična fizika, neravnovesna statistična mehanika