Entanglement fidelity and measurement of entanglement preserving in quantum processes

Abstract

The entanglement fidelity provides a measure of how well the entanglement between two subsystems is preserved in a quantum process. By using a simple model we show that in some cases this quantity in its original definition fails in the measurement of the entanglement preserving. On the contrary, the modified entanglement fidelity, obtained by using a proper local unitary transformation on a subsystem, is shown to exhibit the behavior similar to that of the concurrence in the quantum evolution.

4 pages, 2 figures. v2: repaired a severe oversight, removed an incorrect claim, added references; v3: version accepted for publication in Phys. Rev. A

References in corpus (1)

• Entanglement fidelity of quantum memories

Cited by in corpus (1)

• Entropy exchange, coherent information and concurrence