论文标题
开放量子系统的时晶过渡中的模式软化
Mode softening in time-crystalline transitions of open quantum systems
论文作者
论文摘要
在这项工作中，我们概括了空间晶体过渡到开放量子系统中时间晶体的旋转软化机理的概念。我们将耗散性的DICKE模型作为一个典型的例子，既表现出连续的时间晶体又表现出离散的时间晶体阶段。我们发现，在接近时间晶体过渡时，响应函数以有限的频率差异，这决定了即将到来的时间晶体的周期。这种差异可以理解为相应集体激发的松弛速率的软化，可以通过复杂平面上的响应函数清楚地看到这一点。使用此模式软化分析，我们预测了我们模型中的时间准晶体阶段，在这种模型中，自组织期和驾驶期是不相同的。
In this work, we generalize the concept of roton softening mechanism of spatial crystalline transition to time crystals in open quantum systems. We study a dissipative Dicke model as a prototypical example, which exhibits both continuous time crystal and discrete time crystal phases.We found that on approaching the time crystalline transition, the response function diverges at a finite frequency, which determines the period of the upcoming time crystal. This divergence can be understood as softening of the relaxation rate of the corresponding collective excitation, which can be clearly seen by the poles of the response function on the complex plane. Using this mode softening analysis, we predict a time quasi-crystal phase in our model, in which the self-organized period and the driving period are incommensurate.
