Decoherence and its Role in the Modern Measurement Problem

TL;DR

This paper clarifies how quantum measurements are handled in modern physics without wavefunction collapse, examines decoherence's role, and discusses its implications for solving the measurement problem.

Contribution

It provides an updated account of quantum measurement practices and analyzes decoherence's impact on the measurement problem in contemporary physics.

Findings

Quantum measurements in practice do not involve wavefunction collapse.

Decoherence explains the apparent classicality without resolving the measurement problem.

Decoherence influences the viability of various solutions to the measurement problem.

Abstract

Decoherence is widely felt to have something to do with the quantum measurement problem, but getting clear on just what is made difficult by the fact that the "measurement problem", as traditionally presented in foundational and philosophical discussions, has become somewhat disconnected from the conceptual problems posed by real physics. This, in turn, is because quantum mechanics as discussed in textbooks and in foundational discussions has become somewhat removed from scientific practice, especially where the analysis of measurement is concerned. This paper has two goals: firstly (sections 1-2), to present an account of how quantum measurements are actually dealt with in modern physics (hint: it doesn't involve a collapse of the wavefunction) and to state the measurement problem from the perspective of that account; and secondly (sections 3-4), to clarify what role decoherence plays in modern measurement theory and what effect it has on the various strategies that have been proposed to solve the measurement problem.