2021/07/31 by Haruki Watanabe
Chemistry · Mathematics · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Canonical ensemble #Charge (physics) #Charge conservation #Chemistry #Conserved quantity #Current (fluid) #Fluctuation theorem #Gibbs state #Ground state #Mathematical physics #Mathematics #Momentum (technical analysis) #Operator (biology) #Physics #Preprint #Quantum #Quantum many-body systems #Quantum mechanics #Quantum, superfluid, helium dynamics #Spectroscopy and Quantum Chemical Studies #State (computer science) #Theoretical and Computational Physics #Thermodynamics #Zero (linguistics) #cond-mat.other #cond-mat.quant-gas #cond-mat.stat-mech #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevresearch.4.013043
published in Physical Review Research 4(1) (American Physical Society) · 8 pages, 1 figure. v2: Typos corrected and new discussions added. To appear in Physical Review Research
arxiv created 2022/01/08 · openalex publication_date 2022/01/21 · arxiv updated 2022/01/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
The Bloch theorem is a general theorem restricting the persistent current associated with a conserved U(1) charge in a ground state or in a thermal equilibrium. It gives an upper bound of the magnitude of the current density, which is inversely proportional to the system size. In a recent paper, Else and Senthil applied the argument for the Bloch theorem to a generalized Gibbs ensemble, assuming the presence of an additional conserved charge, and predicted a nonzero current density in the nonthermal steady state [Else and Senthil, Phys. Rev. B 104, 205132 (2021)]. In this paper, we provide a complementary derivation based on the canonical ensemble, given that the additional charge is strictly conserved within the system by itself. Furthermore, using the example where the additional conserved charge is the momentum operator, we discuss that the persistent current tends to vanish when the system is in contact with an external momentum reservoir in the comoving frame of the reservoir.