Entanglement Preservation and Clauser-Horne Nonlocality in Electromagnetically Induced Transparency Quantum Memories

Fuente: arXiv
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Auteurs principaux: Tseng, Po-Han, Chen, Yong-Fan
Format: Preprint
Publié: 2025
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author Tseng, Po-Han
Chen, Yong-Fan
author_facet Tseng, Po-Han
Chen, Yong-Fan
contents Entanglement preservation in noisy quantum memories represents a long-standing conceptual challenge in quantum information science. While experiments have shown that electromagnetically induced transparency (EIT) memories can store entangled photons, a rigorous theoretical demonstration of whether such memories fundamentally preserve nonlocality has remained elusive. Here we develop a unified open-system model that combines the dark-state polariton formalism with reduced density operator theory to describe the retrieved photon state under realistic ground state decoherence. The analysis reveals that decoherence inevitably transforms an initially pure Bell state into a mixed state and predicts a critical storage efficiency threshold of 89.7%. Above this threshold, the retrieved photon violates the Clauser-Horne inequality, confirming the preservation of nonlocal quantum correlations, whereas below it, nonlocality is lost. This work provides the first systematic theoretical proof that EIT quantum memories can in principle preserve entanglement and nonlocality, thereby resolving a fundamental question in the physics of quantum information storage.
format Preprint
id arxiv_https___arxiv_org_abs_2507_15453
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Entanglement Preservation and Clauser-Horne Nonlocality in Electromagnetically Induced Transparency Quantum Memories
Tseng, Po-Han
Chen, Yong-Fan
Quantum Physics
Entanglement preservation in noisy quantum memories represents a long-standing conceptual challenge in quantum information science. While experiments have shown that electromagnetically induced transparency (EIT) memories can store entangled photons, a rigorous theoretical demonstration of whether such memories fundamentally preserve nonlocality has remained elusive. Here we develop a unified open-system model that combines the dark-state polariton formalism with reduced density operator theory to describe the retrieved photon state under realistic ground state decoherence. The analysis reveals that decoherence inevitably transforms an initially pure Bell state into a mixed state and predicts a critical storage efficiency threshold of 89.7%. Above this threshold, the retrieved photon violates the Clauser-Horne inequality, confirming the preservation of nonlocal quantum correlations, whereas below it, nonlocality is lost. This work provides the first systematic theoretical proof that EIT quantum memories can in principle preserve entanglement and nonlocality, thereby resolving a fundamental question in the physics of quantum information storage.
title Entanglement Preservation and Clauser-Horne Nonlocality in Electromagnetically Induced Transparency Quantum Memories
topic Quantum Physics
url https://arxiv.org/abs/2507.15453