Discrete Time-Crystalline Order in Cavity and Circuit QED Systems
Discrete Time-Crystalline Order in Cavity and Circuit QED Systems
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DOI：
10.1103/physrevlett.120.040404
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发表时间：
2018-01-25
影响因子：
8.6
通讯作者：
Ueda, Masahito
中科院分区：
文献类型：
--
作者：
Gong, Zongping;Hamazaki, Ryusuke;Ueda, Masahito
离散时间晶体是最近提出并通过实验观察到的 Floquet 系统的非平衡动态相，其中局部可观测的频闪动态在驱动周期的整数倍处重复。我们在驱动耗散装置中解决这个问题，重点关注调制开放迪克模型，该模型可以通过腔或电路 QED 系统实现。在热力学极限中，我们采用半经典方法并在离散时间晶体顺序之上发现了丰富的动力学相。在具有很少量子位的深量子体系中，我们发现了瞬态离散时间晶体行为的清晰特征，这在孤立的对应物中是不存在的。我们通过将相变朗道理论推广到 Floquet 开放系统，建立了耗散离散时间晶体的现象学。
Discrete time crystals are a recently proposed and experimentally observed out-of-equilibrium dynamical phase of Floquet systems, where the stroboscopic dynamics of a local observable repeats itself at an integer multiple of the driving period. We address this issue in a driven-dissipative setup, focusing on the modulated open Dicke model, which can be implemented by cavity or circuit QED systems. In the thermodynamic limit, we employ semiclassical approaches and find rich dynamical phases on top of the discrete time-crystalline order. In a deep quantum regime with few qubits, we find clear signatures of a transient discrete time-crystalline behavior, which is absent in the isolated counterpart. We establish a phenomenology of dissipative discrete time crystals by generalizing the Landau theory of phase transitions to Floquet open systems.