Evolution of entanglement for quantum mixed states
Chang‐shui Yu, X. X. Yi, He‐Shan Song · Physical Review A · 2008
A simple relation is introduced for concurrence to describe how much the entanglement of a bipartite system is at least left if either (or both) subsystem undergoes an arbitrary physical process. This provides a lower bound for concurrence of mixed states (pure states are included) in contrast to the upper bound given by Konrad et al. [Nat. Phys. 4, 99 (2008)]. Our results are also suitable for general high-dimensional bipartite quantum systems.