量子网络中容错量子传态的理论研究

Our project aims to study the related theoretical problems in fault-tolerant quantum state transfer in a quantum network. Here the errors in quantum state transfer we consider come from two aspects: the imperfect preparation of the initial states of the quantum network and the noise from the environment during the process of quantum state transfer. The studies done so far mainly focus on the system of a 1/2-spin chain, and a series of important contributions have been made in the field. Along this direction, we will further develop an effective theoretical method to deal with the related quantum many-body dynamics problem, and studies the effect of the environments on quantum state transfer along a 1/2-spin chain. Based on this foundation, we will study fault-tolerant quantum state transfer in a quantum network composed by two-level atoms, three-level atoms, and (or) micro-cavities for one or two dimensional configurations. In addition, we will study how to defend the noise effect from the environment on quantum state transfer in some concrete systems (e.g. Josephson-junction micro-cavity system). Our studies will laid the theoretical foundation for fault-tolerant quantum state transfer in quantum network, and presents the theoretical proposal of fault-tolerant quantum state transfer in concrete physical systems.

本项目立项研究量子网络中容错量子态传送相关的理论问题。这里量子传态中的容错性所针对的错误主要来源于量子网络中粒子初态制备的不完美和在传态过程中环境噪声的影响。已有的量子网络中量子传态方向的研究工作主要集中在一维1/2自旋链体系，目前已取得了一系列重要的进展。本项目首先将进一步深化该方向的研究，如发展有效的理论方法处理相关的量子动力学问题，以及研究外界环境对一维自旋链中量子传态的影响。在此基础上，我们将研究由微腔、二能级或三能级（人工）原子组成的一维或二维量子网络中容错性量子传态问题。特别是，我们将研究微腔中任意Fock态的传递，以及研究具体物理体系中（如超导Josephson结－微腔体系）抗外界环境干扰的量子传态方案。我们的研究将为量子网络中容错性量子传态的发展提供理论。

本项目研究了量子网络中容错量子传态的相关理论问题，取得了如下主要成果：.（1）提出了实验可行的基于时间反演破缺的量子态单向传送方案；（2）提出.了基于一维微腔阵列的无需初始化的任意单模量子态传送方案；（3）研究了一.维腔阵列中单光子散射问题，散射物体包括有一定距离的双原子，以及超腔QED，.发现并解释了光散射中的新奇量子现象；（4）提出了用量子信息方法刻画拓扑.序的方法。我们的工作为实验上开展容错性量子计算奠定了坚实的理论基础，从.理论上预言新奇量子现象，并结合量子信息给出了拓扑序度量的新方法。