SciPost Physics

SciPost Phys. 15, 024 (2023) · published 24 July 2023

• doi: 10.21468/SciPostPhys.15.1.024
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Abstract

Answers to the question how a classical world emerges from underlying quantum physics are revisited, connected and extended as follows. First, three distinct concepts are compared: decoherence in open quantum systems, consistent/decoherent histories and Kolmogorov consistency. Second, the crucial role of quantum Markovianity (defined rigorously) to connect these concepts is established. Third, using a random matrix theory model, quantum effects are shown to be exponentially suppressed in the measurement statistics of slow and coarse observables despite the presence of large amount of coherences. This is also numerically exemplified, and it highlights the potential and importance of non-integrability and chaos for the emergence of classicality.

• Strasberg et al., Classicality, Markovianity, and local detailed balance from pure-state dynamics
  Phys. Rev. A 108, 012225 (2023) [Crossref]
• Laverick et al., Quantum State Smoothing Cannot Be Assumed Classical Even When the Filtering and Retrofiltering Are Classical
  PRX Quantum 4, 040340 (2023) [Crossref]
• Saha et al., Thermalization of isolated quantum many-body system and the role of entanglement
  Physics Letters A 509, 129501 129501 (2024) [Crossref]