Why decoherence solves the measurement problem

TL;DR

This paper argues that decoherence explains the measurement problem in quantum physics by showing how local mixed states emerge from entanglement while the global state remains coherent, resolving longstanding dilemmas.

Contribution

It clarifies how decoherence leads to local outcomes in measurement without requiring wavefunction collapse, providing a comprehensive resolution to the measurement problem.

Findings

Decoherence results in local mixed states during measurement.

The global quantum state remains coherent and uncollapsed.

Experimental evidence supports the decoherence-based solution.

Abstract

Although the solution, within standard quantum physics, of the problem of outcomes has been published several times, many authors continue to treat measurement as an unsolved fundamental dilemma. The solution lies in the formation of entangled subsystems, the non-local nature of the measurement state, and the resulting distinction between mixed-state local outcomes and the pure-state global outcome. Upon "measurement" (i.e. entanglement), the quantum system and its measurement apparatus both decohere and collapse into local mixed states while the unitarily-evolving global state remains coherent and un-collapsed. The states we observe are the local, collapsed states. Considerable experimental evidence supports this conclusion. Theoretical objections to this conclusion are rebutted, and a new perspective on measurement and entanglement is noted.