纠缠态表象在热场动力学中的应用  

Application of Entangled State Representation in Thermal Field Dynamics

作　　者：任刚 刘忠义 杜建明 余海军 张文海 REN Gang;LIU Zhongyu;DU Jianming;YU Haijun;ZHANG Wenhai(Department of Optoelectronic Information Science and Engineering,School of Electrical and Electronics Engineering,Huainan Normal University Huainan 202036)

机构地区：[1]淮南师范学院电子工程学院光电信息科学与工程系,淮南202036

出　　处：《低温物理学报》2021年第3期187-192,共6页Low Temperature Physical Letters

基　　金：安撤省教育厅自然科学基金(批准号:KJ2019A0688);安徽省省级教研项目(批准号:2018mooc125)资助的课题.

摘　　要：大多数量子系统都与外界环境之间存在某种热交换或热纠缠,受量子光学双光子纠缠态表象启发,本文将建立热纠缠态表象.根据Takahashi与Umezawa提出的热场动力学理论,热场混合态可以等效为一个量子纯态.因此,任意量子态在环境温度不为零(T≠0)时,系综期望值可以等效成对量子纯态的平均值.在温度趋向于无穷大时,可以得到热真空态的极限形式.类似于相干态,利用平移算符对热真空态极限形式做平移操作后,即可得到热相干态(也称为热纠缠态).热纠缠态表象可以将密度算符ρ=|m><n|中的左矢部分转化为与环境有关的ρ=|m><n|,从而可以使讨论量子态在热环境的演化变得方便快捷.Most quantum systems have thermal exchange or entanglement with the external environment.Inspired by the two-photon entangled representation in quantum optics,a novel thermal entangled state representation is established.According to the thermal field dynamics theory proposed by Takahashi and Umezawa»the thermal mixed state is equivalent to a quantum pure state.Therefore,when the ambient temperature of any quantum state is not zero(T≠0),expected value for quantum system is equivalent to the average value of quantum pure states.When the temperature tends to infinity,the limit form of the thermal vacuum state is obtained.Similar to the coherent state,the thermal coherent state(also called the thermal entangled state)is obtained by operating the displacement operator on the thermal vacuum state.The thermal entangled representation may be used to transform the bra of the density operator |ρ〉=|m>〈n| into environment-related ones |ρ〉=|m>〈n|,which can make it easier and faster to discuss the evolution of quantum states in thermal environments.

关 键 词：希尔伯特空间 量子主方程 热真空态 平移算符 

分 类 号：O431.2[机械工程—光学工程]