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The European Physical Journal C

Gaussian quantum steering for continuous variables sharing in an expanding universe

Hengyu Wu, Xiaolong Gong, Tonghua Liu, Shu-Min Wu

Published Aug 27, 2024• 5 citations
Publisher

Abstract

Abstract Realistic quantum systems are affected by the expanding universe in their preparation and quantum information processing. In this paper, we study the relationship between the Gaussian quantum steering distribution and the parameters of the expanding universe. The expansion process of the universe can be described as a channel acting on a two-mode squeezed Gaussian state, with the evolution of quantum steering from the asymptotic past to the asymptotic future resulting in new distributions parameterized by cosmic parameters. We find that Gaussian quantum steering is more sensitive to the volume change of the expanding universe than the expansion rate, and the Gaussian quantum steering generated by particles with suitable mass and small momentum is more affected by the expanding universe.

DOI
10.1140/epjc/s10052-024-13226-2

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Abstract Quantum communication networks rely on quantum teleportation, a process where an unknown quantum state is transmitted between sender and receiver via entangled states and classical communication. In our study, we utilize a continuous variable two-mode squeezed vacuum state as the primary resource for quantum teleportation, shared by Alice and Bob, while exposed to a squeezed thermal environment. Secure quantum teleportation necessitates a teleportation fidelity exceeding 2/3 and the establishment of two-way steering of the resource state. We investigate the temporal evolution of steering and teleportation fidelity to determine critical parameter values for secure quantum teleportation of a coherent Gaussian state. Our findings reveal constraints imposed by temperature, dissipation rate, and squeezing parameters of the squeezed thermal reservoir on the duration of secure quantum teleportation. Intriguingly, we demonstrate that increasing the initial state’s squeezing parameter effectively extends the temporal window for successful secure quantum teleportation.