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arXiv · 2202.09328

Redundantly amplified information suppresses quantum correlations in many-body systems

D. Girolami·A. Touil·B. Yan·S. Deffner·W. H. Zurek
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Abstract

We establish bounds on quantum correlations in many-body systems. They reveal what sort of information about a quantum system can be simultaneously recorded in different parts of its environment. Specifically, independent agents who monitor environment fragments can eavesdrop only on amplified and redundantly disseminated - hence, effectively classical - information about the decoherence-resistant pointer observable. We also show that the emergence of classical objectivity is signaled by a distinctive scaling of the conditional mutual information, bypassing hard numerical optimizations. Our results validate the core idea of Quantum Darwinism: objective classical reality does not need to be postulated and is not accidental, but rather a compelling emergent feature of quantum theory that otherwise - in absence of decoherence and amplification - leads to "quantum weirdness". In particular, a lack of consensus between agents that access environment fragments is bounded by the information deficit, a measure of the incompleteness of the information about the system.

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D. Girolami, A. Touil, B. Yan, S. Deffner, W. H. Zurek. 2022-02-18. Redundantly amplified information suppresses quantum correlations in many-body systems. https://doi.org/10.1103/physrevlett.129.010401

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