Coexistence of ergodic and nonergodic behavior and level spacing statistics in a one-dimensional model of a flat band superconductor

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Authors

Date

2025-01

Department

Department of Applied Physics

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Mcode

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Language

en

Pages

17

Series

Physical Review Research, Volume 7, issue 1, pp. 1-17

Abstract

Motivated by recent studies of the projected dice lattice Hamiltonian [K. Swaminathan, Phys. Rev. Res. 5, 043215 (2023)2643-156410.1103/PhysRevResearch.5.043215], we introduce the on-site/bond singlet (OBS) model, a one-dimensional model of a flat band superconductor, in order to better understand the quasiparticle localization and interesting coexistence of ergodic and nonergodic behavior present in the former model. The OBS model is the sum of terms that have direct counterparts in the projected dice lattice Hamiltonian, each of which is parameterized by a coupling constant. Exact diagonalization reveals that the energy spectrum and nonequilibrium dynamics of the OBS model are essentially the same as that of the dice lattice for some values of the coupling constants. The quasiparticle localization and breaking of ergodicity manifest in a striking manner in the level spacing distribution. Its near Poissonian form provides evidence for the existence of local integrals of motion and establishes the OBS model as a nontrivial integrable generalization of the projected Creutz ladder Hamiltonian. These results show that level spacing statistics is a promising tool to study quasiparticle excitations in flat band superconductors.

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Publisher Copyright:© 2025 authors. Published by the American Physical Society.

Keywords

Condensed Matter - Superconductivity, Condensed Matter - Statistical Mechanics

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DOI

10.1103/PhysRevResearch.7.013318

Citation

Teeriaho, M, Linho, V V, Swaminathan, K & Peotta, S 2025, 'Coexistence of ergodic and nonergodic behavior and level spacing statistics in a one-dimensional model of a flat band superconductor', Physical Review Research, vol. 7, no. 1, 013318, pp. 1-17. https://doi.org/10.1103/PhysRevResearch.7.013318

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https://urn.fi/URN:NBN:fi:aalto-202511058659

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[article-cris] Perustieteiden korkeakoulu / SCI