Decoherent quench dynamics across quantum phase transitions
Decoherent quench dynamics across quantum phase transitions
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DOI：
10.21468/scipostphys.11.4.084
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发表时间：
2021-03
期刊：
影响因子：
5.5
通讯作者：
W. Kuo;D. Arovas;S. Vishveshwara;Yi-Zhuang You
中科院分区：
文献类型：
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作者：
W. Kuo;D. Arovas;S. Vishveshwara;Yi-Zhuang You
我们提出了一个配方，调查淬火动力学量子相变中存在的退相干。我们制定退相干动力学诱导的连续量子非爆破测量的瞬时哈密顿量。我们推广了广泛研究的通用Kibble-Zurek行为的线性时间驱动器的临界点。我们确定了一个强的退相干制度，其中的退相干时间是短于标准的相关时间，它的变化作为上述基态的间隙的倒数。在这种情况下，我们发现冻结时间\bar{t}\sim\tau^{{2\nu z}/（{1+2\nu z}）}t-τ τ2νz/（1+2νz）（当系统福尔斯失去平衡时）和相关的冻结长度\bar{\xi}\sim\tau^{\nu/（{1+ 2\nuz}）}的幂律τν/（1+2νz）表示相对于猝灭速率1/τ 1/τ的幂律缩放，其中，指数取决于与跃迁相关联的相关长度指数\nuν和动力学指数zz。普适指数不同于标准Kibble-Zurek标度。我们明确地证明了这种缩放行为的实例中的拓扑转变的陈省身绝缘体系统。我们表明，冻结出的时间尺度可以从霍尔电导率的弛豫探测。此外，在引入无序打破平移不变性，我们演示了如何淬火结果的不平衡的激发密度的区域，其特征在于由一个紧急的长度尺度，这也显示了普遍的缩放。我们进行数值模拟，以确认我们的分析预测和证实的缩放参数，我们假设为普遍的主机系统。
We present a formulation for investigating quench dynamics across quantum phase transitions in the presence of decoherence. We formulate decoherent dynamics induced by continuous quantum non-demolition measurements of the instantaneous Hamiltonian. We generalize the well-studied universal Kibble-Zurek behavior for linear temporal drive across the critical point. We identify a strong decoherence regime wherein the decoherence time is shorter than the standard correlation time, which varies as the inverse gap above the groundstate. In this regime, we find that the freeze-out time \bar{t}\sim\tau^{{2\nu z}/({1+2\nu z})}t-∼τ2νz/(1+2νz) for when the system falls out of equilibrium and the associated freeze-out length \bar{\xi}\sim\tau^{\nu/({1+2\nu z})}ξ‾∼τν/(1+2νz) show power-law scaling with respect to the quench rate 1/\tau1/τ, where the exponents depend on the correlation length exponent \nuν and the dynamical exponent zz associated with the transition. The universal exponents differ from those of standard Kibble-Zurek scaling. We explicitly demonstrate this scaling behavior in the instance of a topological transition in a Chern insulator system. We show that the freeze-out time scale can be probed from the relaxation of the Hall conductivity. Furthermore, on introducing disorder to break translational invariance, we demonstrate how quenching results in regions of imbalanced excitation density characterized by an emergent length scale which also shows universal scaling. We perform numerical simulations to confirm our analytical predictions and corroborate the scaling arguments that we postulate as universal to a host of systems.