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Entanglement fidelity and measurement of entanglement preservation in quantum processes

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.

arXiv:0704.2973Physical Review AJul 2, 200711 citations

Entanglement fidelity is not a good measurement of entanglement preserving

Yang Xiang, Shi‐Jie Xiong

Apr 23, 20070 citations

Entanglement Fidelity as a Measure of Preservation of Entanglement in Local Noisy Process

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.

Communications in Theoretical PhysicsJun 1, 20111 citation

Entanglement fidelity and measure of entanglement

Vahid Azimi Mousolou

arXiv:1911.10854Quantum Information ProcessingAug 31, 202010 citations

Optimal fidelity for a quantum channel may be attained by nonmaximally entangled states

Somshubhro Bandyopadhyay, Anindita Ghosh

We consider the problem of establishing a two-qubit entangled state of optimal fidelity across a noisy quantum channel when only a single use of the channel and local postprocessing by trace-preserving operations are allowed. We show that the optimal fidelity is obtained only when part of an appropriate nonmaximally entangled state is transmitted through the channel. The entanglement of this state can be vanishingly small when the channel becomes very noisy. Moreover, in the optimal case no further local processing is required to enhance the fidelity. We further show that local postprocessing can enhance fidelity if and only if the amount of noise is larger than a critical value and entanglement of the transmitted state is bounded from below. A notable consequence of these results is that the ordering of states under an entanglement monotone can be reversed even when the states undergo the same local interaction via a trace-preserving, completely positive map.We consider the problem of establishing a two-qubit entangled state of optimal fidelity across a noisy quantum channel when only a single use of the channel and local postprocessing by trace-preserving operations are allowed. We show that the optimal fidelity is obtained only when part of an appropriate nonmaximally entangled state is transmitted through the channel. The entanglement of this state can be vanishingly small when the channel becomes very noisy. Moreover, in the optimal case no further local processing is required to enhance the fidelity. We further show that local postprocessing can enhance fidelity if and only if the amount of noise is larger than a critical value and entanglement of the transmitted state is bounded from below. A notable consequence of these results is that the ordering of states under an entanglement monotone can be reversed even when the states undergo the same local interaction via a trace-preserving, completely positive map.

arXiv:1209.3494Physical Review AAug 24, 201220 citations

Entanglement measures induced by fidelity-based distances

Yu Jing Guo, Lin Zhang, Huting Yuan

Quantum Information ProcessingAug 24, 20208 citations

Entanglement Fidelity as a Measure of Preservation of Entanglement in Local Noisy Process

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Entanglement Fidelity as a Measure of Preservation of Entanglement in Local Noisy Process

Abstract

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