Many quantum systems of interest are initially correlated with their environments and the reduced dynamics of open systems are an interesting while challenging topic. Affine maps, as an extension of completely positive maps, are a useful tool to describe the reduced dynamics of open systems with initial correlations. However, it is unclear what kind of initial state shares an affine map. In this study, we give a sufficient condition of initial states, in which the reduced dynamics can always be described by an affine map. Our result shows that if the initial states of the combined system constitute a convex set, and if the correspondence between the initial states of the open system and those of the combined system, defined by taking the partial trace, is a bijection, then the reduced dynamics of the open system can be described by an affine map.
. [J]. 中国物理快报, 2015, 32(4): 40302-040302.
ZHANG Da-Jian, LIU Chong-Long, TONG Dian-Min. Dynamics of Open Systems with Affine Maps. Chin. Phys. Lett., 2015, 32(4): 40302-040302.
2015, Vol. 32 
