Entanglement and diagonal entropies after a quench with no pair structure

Bertini, Bruno (author), Tartaglia, Elena (author), Calabrese, Pasquale (author)

A typical working condition in the study of quantum quenches is that the initial state produces a distribution of quasiparticle excitations with an opposite-momentum-pair structure. In this work we investigate the dynamical and stationary properties of the entanglement entropy after a quench from initial states which do not have such structure: instead of pairs of excitations they generate $\nu$-plets of correlated excitations with $\nu$ > 2. Our study is carried out focusing on a system of non-interacting fermions on the lattice. We study the time evolution of the entanglement entropy showing that the standard semiclassical formula is not applicable. We propose a suitable generalisation which correctly describes the entanglement entropy evolution and perfectly matches numerical data. We finally consider the relation between the thermodynamic entropy of the stationary state and the diagonal entropy, showing that when there is no pair structure their ratio depends on the details of the initial state and lies generically between 1/2 and 1.

• Language: English
• Keywords: quantum statistical mechanics, integrable systems, quantum entanglement
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication version: Author Accepted Manuscript
• Year: 2018
• Number of pages: 31 str.
• Numbering: Vol. 2018, art. no. 063104
• PID: 20.500.12556/RUL-105237
• UDC: 536.93
• ISSN on article: 1742-5468
• DOI: 10.1088/1742-5468/aac73f
• COBISS.SI-ID: 3264868
• Publication date in RUL: 13.11.2018

Record is a part of a journal

• Title: Journal of statistical mechanics
• Shortened title: J. stat. mech.
• Publisher: IOP Publishing
• ISSN: 1742-5468
• COBISS.SI-ID: 21517607

Secondary language

• Language: Slovenian
• Keywords: kvantna statistična mehanika, integrabilni sistemi, kvantna prepletenost

Projects

• Funder: EC - European Commission
• Funding programme: H2020
• Project number: 694544
• Name: Open many-body non-equilibrium systems
• Acronym: OMNES