量子關聯(lián)的動力學研究.pdf

1、中國科學技術大學博士學位論文量子關聯(lián)的動力學研究姓名：蔣峰建申請學位級別：博士專業(yè)：粒子與原子核物理指導教師：杜江峰;石名俊2011-05-01ABSTRACTABSTRACTQuantum information processing, which is combined the quantum mechanics andthe information science, have developed fast over the pas

2、t decades. These bring newviewpoints to both Physics and Computing. In this dissertation, we focus on the dynam-ics evolution of quantum correlation in different decoherence models. We have knownthat the entanglement is

3、important for quantum information processing. Recently, theresearch of quantum correlation, often measured by quantum discord, attract numerousattentions. Our works on this field are as follows:(1). We presented an analy

4、tic result for the entanglement evolution for arbitrarytwo-qubit pure state under amplitude damping and particularly phase damping channel.The disentanglement time and the relationship between it and the form of initial

5、stateare given explicitly. The lower bounds of disentanglement time are obtained and shownto be the monotone functions of initial concurrence.(2). We reveal a relationship between the original definition of discord base

6、on themeasurements and the geometric viewpoint with no need for measurements , from whichtwo-qubit quantum discord can be described clearly. The known results about X statediscord are restated in the directly perceivable

7、 geometric language. As a consequence,the dynamics of classical correlations and quantum discord for an X state in the presenceof decoherence is endowed with geometric interpretation. We also discussed thoroughlythe case

8、 of two-qubit rank- two states. An analytical expression for the quantum discordis obtained by means of Koashi-Winter relation. At last, we discuss the dynamicalevolution of arbitrary 2-qubit pure states through a one-si

9、ded channel.(3). We study dynamical evolution of a solid-spin state surrounded by a nuclearspin-bath in a micro-cavity. In the simplified model, we assume the interactions betweenthe system spin and the bath are Ising co

10、upling, and there is no interaction between thespin-bath and the optical field in the cavity. We also investigate quantum correlationdynamical evolutions of a two-qubit state immersed a common bath by using a Marko-vian

11、quantum master equation, and we find the quantum discord still exist even thoughthe entanglement is absent thoroughly in the evolution.Keywords: Quantum entanglement, Quantum correlation, Decoherence, Micro-Cavity,Quantu