Critical spectrum of the anisotropic two-photon quantum Rabi model

Fuente: arXiv
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Hauptverfasser: Li, Jiong, Braak, Daniel, Chen, Qing-Hu
Format: Preprint
Veröffentlicht: 2024
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author Li, Jiong
Braak, Daniel
Chen, Qing-Hu
author_facet Li, Jiong
Braak, Daniel
Chen, Qing-Hu
contents The anisotropic two-photon quantum Rabi model is studied using the Bogoliubov operator approach. The doubly degenerate exceptional states are identified through analytical methods. By adjusting the position of the last exceptional point belonging to two adjacent energy levels, we derive a condition for the absence of the discrete spectrum at the critical coupling where ``spectral collapse" occurs. In this special case, the spectrum becomes fully continuous above a threshold energy, with no bound states existing, whereas the ground state remains gapped in the general case. This also signals a quantum phase transition. More interestingly, we rigorously find that a finite number of bound states exist between two anisotropy dependent critical atomic frequencies, with infinitely many bound states beyond this frequency regime. In this manner, all issues in the two-photon quantum Rabi model are resolved.
format Preprint
id arxiv_https___arxiv_org_abs_2412_20437
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Critical spectrum of the anisotropic two-photon quantum Rabi model
Li, Jiong
Braak, Daniel
Chen, Qing-Hu
Quantum Physics
The anisotropic two-photon quantum Rabi model is studied using the Bogoliubov operator approach. The doubly degenerate exceptional states are identified through analytical methods. By adjusting the position of the last exceptional point belonging to two adjacent energy levels, we derive a condition for the absence of the discrete spectrum at the critical coupling where ``spectral collapse" occurs. In this special case, the spectrum becomes fully continuous above a threshold energy, with no bound states existing, whereas the ground state remains gapped in the general case. This also signals a quantum phase transition. More interestingly, we rigorously find that a finite number of bound states exist between two anisotropy dependent critical atomic frequencies, with infinitely many bound states beyond this frequency regime. In this manner, all issues in the two-photon quantum Rabi model are resolved.
title Critical spectrum of the anisotropic two-photon quantum Rabi model
topic Quantum Physics
url https://arxiv.org/abs/2412.20437