Piotr Tokarczyk (Author), Lev Vidmar (Author), Patrycja Łydżba (Author)

Abstract

Quadratic Hamiltonians that exhibit single-particle quantum chaos are called quantum-chaotic quadratic Hamiltonians. One of their hallmarks is single-particle eigenstate thermalization introduced in Łydżba et al. [Phys. Rev. B 104, 214203 (2021)], which describes statistical properties of matrix elements of observables in single-particle eigenstates. However, the latter has been studied only in quantum-chaotic quadratic Hamiltonians that obey the U(1) symmetry. Here, we focus on quantum-chaotic quadratic Hamiltonians that break the U(1) symmetry and, hence, their “single-particle” eigenstates are actually single-quasiparticle excitations introduced on the top of a many-body state. We study their wave functions and matrix elements of one-body observables, for which we introduce the notion of single-quasiparticle eigenstate thermalization. Focusing on spinless fermion Hamiltonians in three dimensions with local hopping, pairing, and on-site disorder, we also study the properties of disorder-induced near zero modes, which give rise to a sharp peak in the density of states at zero energy. Finally, we numerically show equilibration of observables in many-body eigenstates after a quantum quench. We argue that the latter is a consequence of single-quasiparticle eigenstate thermalization, in analogy to the U(1) symmetric case from Łydżba et al. [Phys. Rev. Lett. 131, 060401 (2023)].

Keywords

statistična fizika;statistical physics;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL FMF - Faculty of Mathematics and Physics
UDC: 536.9
COBISS: 193901571 Link will open in a new window
ISSN: 2470-0045
Views: 29
Downloads: 3
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Other data

Secondary language: Slovenian
Secondary keywords: statistična fizika;
Type (COBISS): Article
Pages: str. 024102-1-024102-17
Volume: ǂVol. ǂ109
Issue: ǂiss. ǂ2
Chronology: 2024
DOI: 10.1103/PhysRevE.109.024102
ID: 23530191