Critical Spectrum and Quantum Criticality in the Two-Photon Rabi-Stark Model

Fuente: arXiv
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Autori principali: Li, Jiong, Chen, Qing-Hu
Natura: Preprint
Pubblicazione: 2025
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author Li, Jiong
Chen, Qing-Hu
author_facet Li, Jiong
Chen, Qing-Hu
contents We investigate the spectral properties and quantum criticality of the two-photon Rabi-Stark model. Using the exact solution of this model, we rigorously derive a condition for complete spectral collapse, where all bound states vanish. In this case, the energy gap closes at a critical coupling, signaling a continuous quantum phase transition. The corresponding gap exponent differs from those in both the one-photon Rabi-Stark model and the quantum Rabi model, suggesting a distinct universality class. While in the general case, an infinite number of discrete bound states exist when spectral collapse occur and the energy gap remains open. By mapping to an inverse square potential well, these bound levels approach the threshold energy exponentially. Our results offer new insights into novel spectral phenomena in nonlinear quantum Rabi models, with potential implications for experimental realizations in circuit QED and trapped ion systems.
format Preprint
id arxiv_https___arxiv_org_abs_2505_20703
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Critical Spectrum and Quantum Criticality in the Two-Photon Rabi-Stark Model
Li, Jiong
Chen, Qing-Hu
Quantum Physics
We investigate the spectral properties and quantum criticality of the two-photon Rabi-Stark model. Using the exact solution of this model, we rigorously derive a condition for complete spectral collapse, where all bound states vanish. In this case, the energy gap closes at a critical coupling, signaling a continuous quantum phase transition. The corresponding gap exponent differs from those in both the one-photon Rabi-Stark model and the quantum Rabi model, suggesting a distinct universality class. While in the general case, an infinite number of discrete bound states exist when spectral collapse occur and the energy gap remains open. By mapping to an inverse square potential well, these bound levels approach the threshold energy exponentially. Our results offer new insights into novel spectral phenomena in nonlinear quantum Rabi models, with potential implications for experimental realizations in circuit QED and trapped ion systems.
title Critical Spectrum and Quantum Criticality in the Two-Photon Rabi-Stark Model
topic Quantum Physics
url https://arxiv.org/abs/2505.20703