Density Operator and Multitime Correlation Functions for Open Systems
Density Operator and Multitime Correlation Functions for Open Systems
复制标题
开放系统的密度算子和多次相关函数
DOI：
10.1103/physreva.3.1723
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发表时间：
1971
影响因子：
2.9
通讯作者：
F. Haake
中科院分区：
文献类型：
--
作者：
F. Haake
我们用非酉时间演化算子来描述开放系统 S 的动力学。后者被定义为求解使用 Zwanzig 投影仪技术获得的 S 密度算子的广义主方程。 S 的可观测量的多时间相关函数用该时间演化算子来表达。我们的结果概括了对于开放系统的马尔可夫运动有效的众所周知的涨落耗散（或回归）定理。此外，它们可以用来结合密度算子和格林函数方法来处理开放系统。作为一个例子，我们处理超导体中延迟的电子-电子相互作用。
We describe the dynamics of an open system S in terms of a nonunitary time evolution operator. The latter is defined to solve the generalized master equation for the density operator of S as obtained using Zwanzig's projector technique. Multitime correlation functions of observables of S are expressed in terms of this time evolution operator. Our results generalize well-known fluctuation dissipation (or regression) theorems valid for Markovian motions of open systems. Moreover, they can be used to combine density-operator and Green's-function methods in dealing with open systems. As an example we treat the retarded electron-electron interaction in superconductors.