摘要：
作为研究系统稳定性的一个重要手段，基于Lyapunov稳定性定理的李亚普诺夫控制方法以广泛应用于数学和自动控制领域。由于这一方法具有精确的分析，较高的鲁棒性，以及有效避免了一般最优控制中的迭代过程，已经成为了一种新的量子控制理论基础。在此次研究中，通过对一单一qubit上施加的外场进行Lyapunov控制，我们可以由各向异性的两qubit海森堡自旋链得到任意的Bell态，这一方法适用于所有以Bell态为基矢的希尔伯特空间中的初始态，并且所得到目标态也是渐近稳定的。

报告二：博士生报告
时间：16:40-17:10

题  目： Quantum phase gates based on surface plasmons of nanoparticles   

报告人：   任俊   
摘要：The Dicke subradiance and superradiance resulting from the interaction between surface plasmons of a nanosphere and an ensemble of quantum emitters have been investigated using a Green’s function approach. Based on such an investigation, we propose a scheme for a deterministic multi-qubit quantum phase gate. As an example, two-qubit, three-qubit, and four-qubit quantum phase gates have been designed and analyzed in detail. Phenomena due to the losses in the metal are discussed. Potential applications of these phenomena to quantum-information processing are anticipated. We also studied the entanglement and spontaneous decay of atoms in the hot spot.

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