Eavesdropping on the Decohering Environment: Quantum Darwinism, Amplification, and the Origin of Objective Classical Reality

Journal Article · 05 January 2022 · Physical Review Letters

DOI: https://doi.org/10.1103/physrevlett.128.010401 · OSTI ID:1853926

Touil, Akram  ^[1]; Yan, Bin  ^[2]; Girolami, Davide  ^[3]; Deffner, Sebastian  ^[4]; Zurek, Wojciech Hubert  ^[2]

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1. Univ. of Maryland Baltimore County (UMBC), Baltimore, MD (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
3. Politecnico di Torino (Italy)
4. Univ. of Maryland Baltimore County (UMBC), Baltimore, MD (United States); Univ. Estadual de Campinas, Sao Paulo (Brazil)

“How much information about a system S can one extract from a fragment F of the environment E that decohered it?” is the central question of Quantum Darwinism. To date, most answers relied on the quantum mutual information of SF, or on the Holevo bound on the channel capacity of F to communicate the classical information encoded in S. Furthermore, these are reasonable upper bounds on what is really needed but much harder to calculate—the accessible information in the fragment F about S. We consider a model based on imperfect c-not gates where all the above can be computed, and discuss its implications for the emergence of objective classical reality. We find that all relevant quantities, such as the quantum mutual information as well as various bounds on the accessible information exhibit similar behavior. In the regime relevant for the emergence of objective classical reality this includes scaling independent of the quality of the imperfect c-not gates or the size of E, and even nearly independent of the initial state of S.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1853926
• Report Number(s): LA-UR-21-20437
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 1 Vol. 128; ISSN 0031-9007
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English