对应负二项式光场的热真空态及其应用  

Thermo-vacuum state in a negative binomial optical field and its application

作　　者：万志龙[1,2] 范洪义[1] 

机构地区：[1]中国科学技术大学材料科学与工程系,合肥230026 [2]常州工学院数理与化工学院,常州213002

出　　处：《物理学报》2015年第19期31-36,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11175113)资助的课题~~

摘　　要：有限温度下的光场理论的核心是引入热真空态,它也是利用量子统计手段全面研究电磁场的基础.本文在Takahashi和Umezawa的热场动力学理论基础上,首次采用有序算符内的积分方法对负二项式光场ρs=∞∑n=0(n+s n)γs+1(1-γ)n|n><n|,寻找相应的热真空态.发现该热真空态是基于在混沌光场所对应的热真空态上的虚模激发,或取负二项式纯态的形式∞∑n=0(n+s n)γs+1(1-γ)n|n,s+>,其中"s"代表虚模自由度.对此热真空态求纯态平均可方便地得到负二项式光场的Wigner函数和光子数涨落.The core of optical field theory at finite temperature is how to introduce the thermo-vacuum state which is the basis of comprehensive investigation of electromagnetic field by virtue of quantum statistic method. Based on the spirit of thermo-field dynamics initiated by Takahashi and Umezawa, we first employ the integration method within the ordered product of operators to search for thermo-vacuum state for the optical negative binomial state （NBS）ρs =∞∑n=0 （ n＋s n ）γs＋1（1-γ）n｜n〉〈n｜.We find that the thermo-vacuum state we search for is just the fictitious-mode excitation in the thermo vacuum state for chaotic state or expressed as∞∑n=0 v u u t （ n＋s n ）γs＋1 （1-γ）n｜n, s-＋-n-,which takes the form of pure negative binomial state. The newly found thermo-vacuum state brings convenience for evaluating the Wigner function of NBS and the fluctuation of photon numbers in NBS.

关 键 词：负二项式光场 热真空态 有序算符内的积分方法 虚模激发 

分 类 号：O441[理学—电磁学]