Sufficient conditions placed on initial system-environment states for positive maps

A system interacting with its environment will give rise to a quantum evolution. After tracing over the environment the net evolution of the system can be described by a linear Hermitian map. It has recently been shown that a necessary and sufficient condition for this evolution to be completely positive is for the initial state to have vanishing quantum discord. In this paper, we provide a sufficient condition for the map to be positive with respect to the initial system-environment correlation. This could lead to ways in which to identify positive but not completely positive maps. Illustrative examples and suggestive procedures are also provided.

No reviews yet.

No comments yet.