论文标题
离散时间量子步行的动力与时间相关的单一噪声
Dynamics of discrete-time quantum walk with time-correlated unitary noise
论文作者
论文摘要
我们研究离散时间量子步行的动力学，视时间相关噪声。噪声在每个步骤之前都被描述为一个单一的硬币型操作员，注意力集中在高斯Ornstein Uhlenbeck过程中产生的噪声，超越了通常的电报噪声，其中随机变量仅由-1和1组成-1和1。在BCH公式的一阶近似值下，BCH公式的一阶近似值，noisisy Pigent of IndiSelet Piment distive distive distive notive notive distective notive notive notive notive distective。主方程给出的动力学与数值模拟在某个步骤中给出的动力学非常吻合，该步骤由噪声参数控制。在数值模拟中观察到长时间嘈杂动力学的两种备注行为，与两个相反的噪声状态相对应：在缓慢的噪声状态下，随着噪声振幅的增加，量子相干性的增加，量子相干性被抑制，并且嘈杂的离散时间量子步行的动力逐渐逐渐转移到经典随机步行的那个经典随机步行中。在快速的噪声状态下，沃克仅限于几个晶格站点，与缓慢的噪声状态相比，波数据包的宽度要窄得多。
We investigate the dynamics of discrete-time quantum walk subject to time correlated noise. Noise is described as an unitary coin-type operator before each step, and attention is focused on the noise generated by a Gaussian Ornstein Uhlenbeck process, going beyond the usual telegraph noise, where the random variables are consist of only -1 and 1. Under the first-order approximation of BCH formula, the master equation of noisy discrete-time quantum walk is derived. The dynamics given by the master equation are in good agreement with those given by numerical simulations within a certain period of steps, which is controlled by noise parameters. Two remarker behaviors of long time noisy dynamics are observed in numerical simulations, corresponding to two opposite noise regimes: in slow noise regime, with the increase of the noise amplitude, the quantum coherence is suppressed, and the dynamics of noisy discrete-time quantum walk gradually transits to that of classical random walk. In fast noise regime, the walker is confined into few lattice sites, and the width of wave packet is much narrower compared with that in slow noise regime.
