Entanglement dynamics for static two-level atoms in cosmic string spacetime
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Regular Article - Theoretical Physics
Entanglement dynamics for static two-level atoms in cosmic string spacetime Pingyang He, Hongwei Yua , Jiawei Hub Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha 410081, Hunan, China
Received: 15 November 2019 / Accepted: 18 January 2020 © The Author(s) 2020
Abstract We study the entanglement dynamics of two static atoms coupled with a bath of fluctuating scalar fields in vacuum in the cosmic string spacetime. Three different alignments of atoms, i.e. parallel, vertical, and symmetric alignments with respect to the cosmic string are considered. We focus on how entanglement degradation and generation are influenced by the cosmic string, and find that they are crucially dependent on the atom-string distance r , the interatomic separation L, and the parameter ν that characterizes the nontrivial topology of the cosmic string. For two atoms initially in a maximally entangled state, the destroyed entanglement can be revived when the atoms are aligned vertically to the string, which cannot happen in the Minkowski spacetime. When the symmetrically aligned two-atom system is initially in the antisymmetric state, the lifetime of entanglement can be significantly enhanced as ν increases. For two atoms which are initially in the excited state, when the interatomic separation is large compared to the transition wavelength, entanglement generation cannot happen in the Minkowski spacetime, while it can be achieved in the cosmic string spacetime when the position of the two atoms is appropriate with respect to the cosmic string and ν is large enough.
1 Introduction Quantum entanglement is one of the most intriguing properties in quantum mechanics [1], and it plays a key role in quantum information and quantum computing [2,3]. However, entanglement degrades due to the inevitable interactions between quantum systems and environment [4], which is one of the main obstacles to the realization of quantum information technologies. In particular, a pair of initially entangled a e-mail:
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atoms can become separable within a finite time, which is referred to as entanglement sudden death [5,6]. However, in certain circumstances, entanglement can be generated rather than destroyed due to indirect interactions between atoms provided by the common bath they immersed in [7–11]. Meanwhile, the destroyed entanglement can also be recreated, depending on the initial state of the two atoms as well as the environment, known as entanglement revival [12]. In recent years, there is increasing interest in the study of entanglement generation in non-inertial frames and in curved spactime [13–24], focusing on the effects of acceleration and spacetime curvature on entanglement dynamics. In this paper, we are concerned with how the entanglement dynamics of a two-atom system is influenced if the atoms are placed in a locally flat spacetime but with nontrivial topology. In
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