量子行走  

Quantum Walk

作　　者：薛鹏 王坤坤 Xue Peng;Wang Kunkun(Beijing Computational Science Research Center,Beijing 100084,China;School of Physics and Optoelectronic Engineering,Anhui University,Hefei 230601,Anhui,China)

机构地区：[1]北京计算科学研究中心,北京100084 [2]安徽大学物理与光电工程学院,安徽合肥230601

出　　处：《光学学报》2024年第2期1-9,共9页Acta Optica Sinica

基　　金：国家自然科学基金(92265209,12025401,12104009)。

摘　　要：作为经典随机行走在量子世界的对应,量子行走在量子相干性和纠缠的作用下,能够以更快的速度使行走者遍历所有位置,可以应用于实现各类算法,加速解决各类问题。此外,作为描述微观粒子动力学演化的有效模型,量子行走还可以作为普适的平台实现所有幺正演化,实现量子态制备、量子逻辑门操作和量子测量等,进而实现信息处理中所有关键步骤。近年来,量子行走中的新机理和新应用的研究成为了人们普遍关注的焦点。首先介绍量子行走基本模型,再结合近年来本课题组在量子行走方向上取得的相关研究成果,介绍量子行走在实现量子通信、量子计算和量子测量方面的研究进展。Significance Classical random walk involves the erratic motion of walkers along some random routes or areas,such as pollen's Brownian motion.Meanwhile,quantum walk is an extension of classical random walk in the quantum realm,and compared with the classical case,it is characterized by quantum superposition and entanglement.The diffusive quantum walk speed increases quadratically rather than linearly as in classical random walk,demonstrating an advantage over classical diffusion by spreading quantum information at a faster rate.Thus,quantum walk can be utilized to develop such quantum algorithms as quantum searching.Compared with classical algorithms,quantum-walk-based algorithms can provide quadratic enhancement.Additionally,as an effective model for describing micro-particle dynamics,quantum walk can serve as a universal platform to achieve arbitrary unitary evolutions,quantum state preparation,quantum logic gate operations,quantum measurements,etc.Finally,quantum walk can realize all key steps in quantum information processing.Progress Recently,many efforts have been devoted to exploring new mechanisms and applications of quantum walk.During a quantum walk,the walker carries quantum information and evolves in different positions.Thus,quantum walk is an effective way to achieve quantum communication and is extensively employed for developing quantum algorithms and achieving universal quantum computation.In addition,quantum walk can realize positive operator measurement and can be applied to quantum precision measurement.Specifically,by controlling various parameters like position,phase,and evolution time across multiple degrees of freedom during the quantum walk,the coin state can be restored to its initial state after a specific evolution time.This approach can be utilized for implementing quantum state transfer.Any arbitrarily high-dimensional quantum state can be prepared by loading a high-dimensional system state onto the walker position state and employing a position-dependent quantum-walk process.This can

关 键 词：量子光学 量子信息处理 量子行走 量子通信 量子计算 量子测量 

分 类 号：O431.2[机械工程—光学工程]