Entanglement fidelity and measure of entanglement

Yu Jing Guo, Lin Zhang, Huting Yuan

Yang Xiang, Shi‐Jie Xiong

Yang Xiang, Shi‐Jie Xiong

A new formula of entanglement fidelity has been introduced, which can serve as a measure of the preservation of entanglement between two initially entangled subsystems exposed to local noisy environments. For a simple model we derive analytic expressions of concurrence and entanglement fidelity and draw the relationship between them. We find that such entanglement fidelity exhibits the behavior similar to that of the concurrence in quantum evolutions.

P. K. Aravind

Yang Xiang, Shi‐Jie Xiong

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 entanglement preservation. On the contrary, the modified entanglement fidelity, obtained by using a proper local unitary transformation on a subsystem, is shown to exhibit behavior similar to that of the concurrence in quantum evolution.

Laleh Memarzadeh, Carlo Cafaro, Stefano Mancini

We design an effective method to investigate the quantum information reclaim from the environment after amplitude damping has occurred. In particular, we address the question of optimal measurement on the environment to perform the best possible correction on two- and three-dimensional quantum systems. While for qubits we show that the entanglement fidelity is the same for all possible measurements, for qutirits we find that different measurements give rise to different values of the entanglement fidelity. By searching over all possible measurements on the environment we uncover the optimal one leading to the maximum entanglement fidelity.