Decoherence without decoherence

TL;DR

This paper argues that quasiclassical behavior in macroscopic systems is a generic property of subsystems, and decoherence should be viewed as maintaining classicality rather than causing it.

Contribution

It challenges the view that decoherence explains the emergence of quasiclassicality, proposing instead that quasiclassicality is inherent and decoherence sustains classicality.

Findings

Quasiclassicality is a common property of subsystems, even without decoherence.

Decoherence is better understood as preserving classicality rather than causing it.

The paper redefines the role of decoherence in the quantum-classical transition.

Abstract

It has been claimed that decoherence of open quantum systems explains the tendency of macroscopic systems to exhibit quasiclassical behavior. We show that quasiclassicality is in fact an unremarkable property, characterizing generic subsystems of environments even in the absence of dynamical decoherence. It is suggested that decoherence is best regarded as explaining the persistence of true classicality, rather than the emergence, rather than the emergence of quasiclassicality.