Grimaudo R, de Castro ASM, Messina A, Solano E, Valenti D. Quantum Phase Transitions for an Integrable Quantum Rabi-like Model with Two Interacting Qubits.
PHYSICAL REVIEW LETTERS 2023;
130:043602. [PMID:
36763445 DOI:
10.1103/physrevlett.130.043602]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/13/2022] [Accepted: 12/22/2022] [Indexed: 06/18/2023]
Abstract
A two-interacting-qubit quantum Rabi-like model with vanishing transverse fields on the qubit pair is studied. Independently of the coupling regime, this model can be exactly and unitarily reduced to two independent single-spin quantum Rabi models, where the spin-spin coupling plays the role of the transverse field. This transformation and the analytical treatment of the single-spin quantum Rabi model provide the key to prove the integrability of our model. The existence of different first-order quantum phase transitions, characterized by discontinuous two-spin magnetization, mean photon number, and concurrence, is brought to light.
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