论文标题
两种模式Dicke模型中的量子混乱和热化
Quantum chaos and thermalization in the two-mode Dicke model
论文作者
论文摘要
我们讨论了量子混乱和两种模型模型中的量子混乱和热化的发作，该模型描述了旋转集合和两种骨气模式之间的偶极相互作用。两种模式的DICKE模型表现出与超级量子相变的垂直于自发断裂或连续对称性的。我们研究了模型的量子阶段中源自Loschmidt Echo信号的倒流外相关器的行为，并表明其指数生长与一般情况下的经典不稳定点不能与经典的不稳定点有关。此外，我们发现，在两模式DICKE模型中可观察到的集体自旋迅速饱和到其长期平均值，并且即使在少量旋转中，其对角线的平均平均值和微炮台平均值之间的一致性也很好。我们表明，在其平均值上可观察到的集体自旋的期望值的时间波动很小，并且随有效系统尺寸而减小，这导致自旋系统的热化。
We discuss the onset of quantum chaos and thermalization in the two-mode Dicke model, which describes the dipolar interaction between an ensemble of spins and two bosonic modes. The two-mode Dicke model exhibits normal to superradiant quantum phase transition with spontaneous breaking either of a discrete or continuous symmetry. We study the behaviour of the fidelity out-of-time-order correlator derived from the Loschmidt echo signal in the quantum phases of the model and show that its exponential growth cannot be related to a classical unstable point in the general case. Moreover, we find that the collective spin observable in the two-mode Dicke model quickly saturates to its long-time average value, and shows very good agreement between its diagonal ensemble average and microcanonical average even for a small number of spins. We show that the temporal fluctuations of the expectation value of the collective spin observable around its average are small and decrease with the effective system size, which leads to thermalization of the spin system.
