Department of Physics and Chemistry "Emilio Segrè", University of Palermo, viale delle Scienze, Building 18, I-90128, Palermo, Italy.
Universidade Estadual de Ponta Grossa, Departamento de Física, CEP 84030-900, Ponta Grossa, Paraná state, Brazil.
Phys Rev Lett. 2023 Jan 27;130(4):043602. doi: 10.1103/PhysRevLett.130.043602.
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.
研究了一种双量子比特量子拉比模型，该模型在量子比特对上具有零横向场。独立于耦合机制，这个模型可以被精确地和幺正地简化为两个独立的单自旋量子拉比模型，其中自旋-自旋耦合扮演了横向场的角色。这种变换以及对单自旋量子拉比模型的解析处理提供了证明我们模型可积性的关键。揭示了不同的一级量子相变的存在，其特征是双自旋磁化强度、平均光子数和纠缠的不连续。
