Quantum many-body spin ratchets

Zadnik, Lenart (author), Ljubotina, Marko (author), Krajnik, Žiga (author), Ilievski, Enej (author), Prosen, Tomaž (author)

Introducing a class of SU(2) invariant quantum unitary circuits generating chiral transport, we examine the role of broken space-reflection and time-reversal symmetries on spin-transport properties. Upon adjusting parameters of local unitary gates, the dynamics can be either chaotic or integrable. The latter corresponds to a generalization of the space-time discretized (Trotterized) higher-spin quantum Heisenberg chain. We demonstrate that breaking of space-reflection symmetry results in a drift in the dynamical spin susceptibility. Remarkably, we find a universal drift velocity given by a simple formula, which, at zero average magnetization, depends only on the values of SU(2) Casimir invariants associated with local spins. In the integrable case, the drift velocity formula is confirmed analytically based on the exact solution of thermodynamic Bethe ansatz equations. Finally, by inspecting the large fluctuations of the time-integrated current between two halves of the system in stationary maximum-entropy states, we demonstrate violation of the Gallavotti-Cohen symmetry, implying that such states cannot be regarded as equilibrium ones. We show that the scaled cumulant generating function of the time-integrated current instead obeys a generalized fluctuation relation.

• Language: English
• Keywords: nonequilibrium statistical mechanics, quantum mechanics, many-body systems
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2024
• Number of pages: Str. 030356-1-030356-26
• Numbering: Vol. 5, iss. 3
• PID: 20.500.12556/RUL-162725
• UDC: 536.9
• ISSN on article: 2691-3399
• DOI: 10.1103/PRXQuantum.5.030356
• COBISS.SI-ID: 209100803
• Publication date in RUL: 26.09.2024

Record is a part of a journal

• Title: PRX quantum
• Shortened title: PRX quantum
• Publisher: American Physical Society
• ISSN: 2691-3399
• COBISS.SI-ID: 103459587

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: neravnovesna statistična mehanika, kvantna mehanika, večdelčni sistemi