Quantum coherence for an atom interacting with an electromagnetic field in the background of cosmic string spacetime
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Quantum coherence for an atom interacting with an electromagnetic field in the background of cosmic string spacetime Zhiming Huang1 Received: 31 May 2020 / Accepted: 19 September 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract We investigate the behaviors of quantum coherence (QC) for an atom coupled to the fluctuating electromagnetic field under the cosmic string spacetime. It is found that vacuum fluctuation, atomic polarization and nontrivial spacetime topology affect the QC behaviors. When deficit angle parameter ν = 1 and atom is far away from the string, the results restore to that of free Minkowski spacetime. When atom lies in the string and is transversely polarizable, the atom seems like a closed system, and QC completely is not affected by the electromagnetic fluctuation. For nonzero atom– string distance, QC presents oscillatory behaviors as atom–string distance changes, and larger deficit angle parameter causes more prominent oscillation. In a sense, the string can protect the QC to some extent, which is similar to the boundary effect in Minkowski spacetime. Besides, this atom eventually evolves to an incoherent state, which does not appear to be related to the initial state and other various parameters; this means QC cannot keep for long evolution time in the cosmic string spacetime. In principle, atomic polarization, atom–string distance and deficit angle parameter provide us more freedom to steer the QC behaviors, which might be useful to sense various cosmic string spacetime and distinguish the cosmic string spacetime from Minkowski spacetime. Keywords Quantum coherence · Cosmic string spacetime · Minkowski spacetime · Electromagnetic field
1 Introduction QC originating from quantum state superposition is the most fundamental quantum feature which has operational significance to quantum theory and quantum technol-
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Zhiming Huang [email protected] School of Economics and Management, Wuyi University, Jiangmen 529020, China 0123456789().: V,-vol
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ogy, such as low-temperature thermodynamics [1,2], quantum biology [3–5], quantum metrology [6,7], quantum key distribution [8], and so on. Some authors demonstrate that QC is closely associated with other quantum correlation resources, such as quantum entanglement and discord [9–12]. Regardless of its significance, only recently Baumgratz et al. [13] proposed a rigorous framework for quantifying QC from the view of resource theory. Based on such a formalism, some QC measures are put forward which satisfy the necessary postulates [13], such as l1 norm of coherence and the relative entropy of coherence [13]. The unavoidable coupling between quantum system and external environment often brings about the loss of quantum resource, such as fluctuation-induced interaction between atom and quantum field. Recently, some authors [14–16] devoted to explore the QC dynamics affected by fluctuating scalar field or electromagnetic field in Minkowski spacetime. Recently, we investigated the QC dynami
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