Percolation assisted excitation transport in discrete-time quantum walks
Percolation assisted excitation transport in discrete-time quantum walks
复制标题
离散时间量子行走中的渗流辅助激发传输
DOI：
--
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
I. Jex
中科院分区：
文献类型：
--
作者：
M. Štefaňák;J. Novotny;I. Jex
沿着耦合量子系统链的激发的相干输运代表了从量子光学到太阳能电池技术的许多应用的有趣问题。研究这种过程的一个方便工具是量子漫步。它们使我们能够以定量的方式确定所有的过程特征。我们研究了一个简单的，高度对称的图表示的一个环上的生存概率和运输效率。激发的传播是由离散时间（杜撰的）量子行走建模。对于两态量子行走，其中激发（步行者）必须离开其实际位置到相邻的站点，生存概率指数衰减和传输效率是1。生存概率的衰减率可以使用演化算子的首特征值来估计。然而，如果允许激发停留在其当前位置，即传播由惰性量子行走建模，则部分波包可以被捕获在原点附近并且永远不会到达接收器。在这种情况下，生存概率不会消失，激发传输效率不高。确定了传输效率对初始状态的依赖性。然而，我们发现，对于一些懒惰的量子行走动力学，消除陷阱效应和有效的激发输运可以实现的环的简化。
Coherent transport of excitations along chains of coupled quantum systems represents an interesting problem with a number of applications ranging from quantum optics to solar cell technology. A convenient tool for studying such processes are quantum walks. They allow us to determine all the process features in a quantitative way. We study the survival probability and the transport efficiency on a simple, highly symmetric graph represented by a ring. The propagation of excitation is modeled by a discrete-time (coined) quantum walk. For a two-state quantum walk, where the excitation (walker) has to leave its actual position to the neighboring sites, the survival probability decays exponentially and the transport efficiency is unity. The decay rate of the survival probability can be estimated using the leading eigenvalue of the evolution operator. However, if the excitation is allowed to stay at its present position, i.e. the propagation is modeled by a lazy quantum walk, then part of the wave-packet can be trapped in the vicinity of the origin and never reaches the sink. In such a case, the survival probability does not vanish and the excitation transport is not efficient. The dependency of the transport efficiency on the initial state is determined. Nevertheless, we show that for some lazy quantum walks dynamical, percolations of the ring eliminate the trapping effect and efficient excitation transport can be achieved.
影响因子：
56.9
作者：
Karski, Michal;Foerster, Leonid;Widera, Artur
通讯作者：
Widera, Artur