Exceptional points and quantum phase transition in a fermionic extension of the Swanson oscillator

Fuente: arXiv
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Auteurs principaux: Sinha, Akash, Ghosh, Aritra, Bagchi, Bijan
Format: Preprint
Publié: 2024
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author Sinha, Akash
Ghosh, Aritra
Bagchi, Bijan
author_facet Sinha, Akash
Ghosh, Aritra
Bagchi, Bijan
contents Motivated by the structure of the Swanson oscillator which is a well-known example of a non-Hermitian quantum system consisting of a general representation of a quadratic Hamiltonian, we propose a fermionic extension of such a scheme which incorporates two fermionic oscillators together with bilinear-coupling terms that do not conserve particle number. We determine the eigenvalues and eigenvectors, and expose the appearance of exceptional points where two of the eigenstates coalesce with the corresponding eigenvectors exhibiting self-orthogonality with respect to the bi-orthogonal inner product. The model admits a quantum phase transition - we discuss the two phases and also demonstrate that the ground-state entanglement entropy exhibits a discontinuous jump indicating the transition between the two phases.
format Preprint
id arxiv_https___arxiv_org_abs_2401_17189
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Exceptional points and quantum phase transition in a fermionic extension of the Swanson oscillator
Sinha, Akash
Ghosh, Aritra
Bagchi, Bijan
Quantum Physics
High Energy Physics - Theory
Mathematical Physics
Motivated by the structure of the Swanson oscillator which is a well-known example of a non-Hermitian quantum system consisting of a general representation of a quadratic Hamiltonian, we propose a fermionic extension of such a scheme which incorporates two fermionic oscillators together with bilinear-coupling terms that do not conserve particle number. We determine the eigenvalues and eigenvectors, and expose the appearance of exceptional points where two of the eigenstates coalesce with the corresponding eigenvectors exhibiting self-orthogonality with respect to the bi-orthogonal inner product. The model admits a quantum phase transition - we discuss the two phases and also demonstrate that the ground-state entanglement entropy exhibits a discontinuous jump indicating the transition between the two phases.
title Exceptional points and quantum phase transition in a fermionic extension of the Swanson oscillator
topic Quantum Physics
High Energy Physics - Theory
Mathematical Physics
url https://arxiv.org/abs/2401.17189