When quantum channel preserves product states
arXiv:1409.5994 · doi:10.1016/S0034-4877(14)00025-1
Abstract
Product states are always considered as the states that don't contain quantum correlation. We discuss here when a quantum channel sends the product states to themselves. The exact forms of such channels are proposed. It is shown that such a quantum channel is a local quantum channel, a composition of a local quantum channel and a flip operation, or such that one of the local states is fixed. Both finite- and infinite-dimensional systems are considered.
4 pages