Berdanier William, Kolodrubetz Michael, Vasseur Romain, Moore Joel E
Department of Physics, University of California, Berkeley, California 94720, USA.
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2017 Jun 30;118(26):260602. doi: 10.1103/PhysRevLett.118.260602. Epub 2017 Jun 29.
A quantum critical system described at low energy by a conformal field theory (CFT) and subjected to a time-periodic boundary drive displays multiple dynamical regimes, depending on the drive frequency. We compute the behavior of quantities including the entanglement entropy and Loschmidt echo, confirming analytic predictions from field theory by exact numerics on the transverse field Ising model and demonstrate universality by adding nonintegrable perturbations. The dynamics naturally separate into three regimes: a slow-driving limit, which has an interpretation as multiple quantum quenches with amplitude corrections from CFT; a fast-driving limit, in which the system behaves as though subject to a single quantum quench; and a crossover regime displaying heating. The universal Floquet dynamics in all regimes can be understood using a combination of boundary CFT and Kibble-Zurek scaling arguments.
一个在低能情况下由共形场论（CFT）描述并受到时间周期边界驱动的量子临界系统，根据驱动频率会呈现出多种动力学状态。我们计算了包括纠缠熵和洛施密特回波在内的物理量的行为，通过对横向场伊辛模型的精确数值计算证实了场论的解析预测，并通过添加不可积微扰证明了其普遍性。动力学自然地分为三个区域：慢驱动极限，可解释为来自CFT的具有振幅修正的多个量子猝灭；快驱动极限，其中系统的行为就好像受到单个量子猝灭一样；以及一个显示出加热现象的交叉区域。所有区域中的普适弗洛凯动力学可以通过边界CFT和基布尔 - 祖雷克标度论证相结合来理解。
