Decoherence and Probability

TL;DR

This paper critically examines decoherence theory's role in explaining probability emergence in quantum mechanics, proposing an alternative semi-classical averaging approach that recovers classical probability under specific conditions.

Contribution

It introduces a novel account combining partial decoherence interpretation with averaging over quasi-probabilities, clarifying when classical probability emerges from quantum systems.

Findings

Decoherence alone does not justify classical probability emergence.

A semi-classical averaging approach can recover classical probabilities.

The approach is valid within a specific coarse-grained context.

Abstract

One cannot justifiably presuppose the physical salience of structures derived via decoherence theory based upon an entirely uninterpreted use of the quantum formalism. Non-probabilistic accounts of the emergence of probability via decoherence are unconvincing. An alternative account of the emergence of probability involves the combination of a partially interpreted decoherence model and an averaging of observables with respect to a positive-definite quasi-probability function and neglect of terms $O(\hbar)$. Our analysis delimits the context in which the combination of decoherence and a semi-classical averaging allows us to recover a classical probability model within an emergent coarse-grained description.