Quantum coherence of multipartite W-state in a Schwarzschild spacetime

Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Synergetic Innovation Center for Quantum Effects and Applications, and Department of Physics, Hunan Normal University Changsha 410081, China

^(a) hszeng@hunnu.edu.cn (corresponding author)

Received: 19 November 2019
Accepted: 18 February 2020

Abstract

We study the quantum coherence and monogamy relationship of a tripartite W-state entangled system for Dirac fields in the background of a Schwarzschild black hole. We find that quantum coherence first decreases and then shows the phenomenon of freezing with the growth of the Hawking temperature. We also find that the l₁ norm of coherence is always equal to the sum of coherence of all bipartite systems for any Hawking temperature, while a similar monogamy relationship for the relative entropy of coherence is absent. Moreover, we extend the related investigations to the N-partite W-state systems. It is shown that a similar monogamy relationship for the l₁ norm of coherence is still satisfied, and the phenomenon of coherence freezing also exists.