Non-degenerate Ground State of the Spin-Boson Model under Abelian Diagonalization

Fuente: arXiv
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Main Authors: Liu, Tao, Wu, Juhao, Ying, Mark
Format: Preprint
Published: 2025
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_version_ 1866909653780135936
author Liu, Tao
Wu, Juhao
Ying, Mark
author_facet Liu, Tao
Wu, Juhao
Ying, Mark
contents By utilizing a unitary transformation, we derive the necessary and sufficient conditions for the degeneracy between the even- and odd-parity energy states of the spin-boson model (SBM). Employing the Rayleigh quotient of matrix algebra, we rigorously prove that the ground state energy of the SBM is lower than the systems lowest possible degenerate energy and possesses a definite parity. Based on the necessary and sufficient conditions for parity breaking, we provide an analytical expression for the parity-breaking critical value, which is closely related to the expansion order and computational accuracy. This expression reproduces the SBM phase diagram obtained by quantum Monte Carlo (QMC) and logarithmic discretization numerical renormalization group (NRG) methods. However, this phase diagram does not characterize the ground state of the system.
format Preprint
id arxiv_https___arxiv_org_abs_2506_14818
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Non-degenerate Ground State of the Spin-Boson Model under Abelian Diagonalization
Liu, Tao
Wu, Juhao
Ying, Mark
Strongly Correlated Electrons
Quantum Physics
By utilizing a unitary transformation, we derive the necessary and sufficient conditions for the degeneracy between the even- and odd-parity energy states of the spin-boson model (SBM). Employing the Rayleigh quotient of matrix algebra, we rigorously prove that the ground state energy of the SBM is lower than the systems lowest possible degenerate energy and possesses a definite parity. Based on the necessary and sufficient conditions for parity breaking, we provide an analytical expression for the parity-breaking critical value, which is closely related to the expansion order and computational accuracy. This expression reproduces the SBM phase diagram obtained by quantum Monte Carlo (QMC) and logarithmic discretization numerical renormalization group (NRG) methods. However, this phase diagram does not characterize the ground state of the system.
title Non-degenerate Ground State of the Spin-Boson Model under Abelian Diagonalization
topic Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2506.14818