Megier Nina, Smirne Andrea, Vacchini Bassano
Dipartimento di Fisica "Aldo Pontremoli", Università degli Studi di Milano, via Celoria 16, 20133 Milan, Italy.
Istituto Nazionale di Fisica Nucleare, Sezione di Milano, via Celoria 16, 20133 Milan, Italy.
Entropy (Basel). 2020 Jul 21;22(7):796. doi: 10.3390/e22070796.
Using a newly introduced connection between the local and non-local description of open quantum system dynamics, we investigate the relationship between these two characterisations in the case of quantum semi-Markov processes. This class of quantum evolutions, which is a direct generalisation of the corresponding classical concept, guarantees mathematically well-defined master equations, while accounting for a wide range of phenomena, possibly in the non-Markovian regime. In particular, we analyse the emergence of a dephasing term when moving from one type of master equation to the other, by means of several examples. We also investigate the corresponding Redfield-like approximated dynamics, which are obtained after a coarse graining in time. Relying on general properties of the associated classical random process, we conclude that such an approximation always leads to a Markovian evolution for the considered class of dynamics.
利用新引入的开放量子系统动力学的局部与非局部描述之间的联系，我们研究了量子半马尔可夫过程情况下这两种表征之间的关系。这类量子演化是相应经典概念的直接推广，在数学上保证了定义明确的主方程，同时涵盖了广泛的现象，可能处于非马尔可夫 regime。特别地，我们通过几个例子分析了从一种主方程转换到另一种主方程时退相干项的出现。我们还研究了相应的类雷德菲尔德近似动力学，它是在时间上进行粗粒化后得到的。基于相关经典随机过程的一般性质，我们得出结论，对于所考虑的这类动力学，这种近似总是导致马尔可夫演化。
