论文标题
非线性两光子拉比 - 哈伯德模型：超级和光子/光子玻色 - 内斯坦冷凝水
Nonlinear two-photon Rabi-Hubbard model: superradiance and photon/photon-pair Bose-Einstein condensate
论文作者
论文摘要
我们使用量子蒙特卡洛（QMC）模拟和密度矩阵重质化组（DMRG）计算研究了一个维度的非线性双光子拉比 - 哈伯（RH）模型的基态相图。我们的模型包括非线性光子 - 光子相互作用项。如果没有此术语，RH模型只有一个相，正常无序相，并且在光子量相互作用的较大值或腔间光子跳跃的较大值下遭受光谱塌陷。光子 - 光子相互作用，无论多么小，稳定系统，该系统现在表现出{\ it两个}量子相变：正常相位为{\ it photon对} superfluid（psf）过渡和psf，而PSF向单个粒子superfluid（spsf）。汉密尔顿的离散$ Z_4 $对称性自发地分为两个阶段：首先，当系统进入PSF时，它会部分断裂，然后在系统最终进入SPSF阶段时完全破裂。我们显示了支持此功能的详细数值结果，并绘制了基态相图。
We study the ground state phase diagram of a nonlinear two-photon Rabi-Hubbard (RH) model in one dimension using quantum Monte Carlo (QMC) simulations and density matrix renormalization group (DMRG) calculations. Our model includes a nonlinear photon-photon interaction term. Absent this term, the RH model has only one phase, the normal disordered phase, and suffers from spectral collapse at larger values of the photon-qubit interaction or inter-cavity photon hopping. The photon-photon interaction, no matter how small, stabilizes the system which now exhibits {\it two} quantum phase transitions: Normal phase to {\it photon pair} superfluid (PSF) transition and PSF to single particle superfluid (SPSF). The discrete $Z_4$ symmetry of the Hamiltonian spontaneously breaks in two stages: First it breaks partially as the system enters the PSF and then completely breaks when the system finally enters the SPSF phase. We show detailed numerical results supporting this, and map out the ground state phase diagram.
