Physical origins and limitations of canonical quantum measurement behavior

TL;DR

This paper explores the physical basis and limitations of quantum measurement behavior by analyzing measurement device microstructures, explaining phenomena like particle tracks and supporting an emergent Born rule consistent with experiments.

Contribution

It provides a detailed, unitarity-consistent analysis of measurement microstructures, explaining canonical quantum measurement behavior and its potential breakdowns.

Findings

Emergent, approximate Born rule supported by experiments

Analysis of measurement device microstructure explains particle detection

Possible breakdown of measurement behavior at very small probabilities

Abstract

I review and augment my work of the last few years on the physical origins and limitations of canonical quantum measurement behavior. Central to this work is a detailed analysis of the microstructure of real measurement devices. Particular attention is paid to the Mott problem, which addresses a simpler version of canonical quantum measurement behavior: It asks why an alpha particle emitted in a nuclear decay produces one and only one track in a cloud chamber. My analysis - entirely consistent with unitarity - leads to an emergent, approximate Born rule supported by experiment, with possible breakdown at very small probability density. I argue that a similar picture applies to other measurement scenarios, including Geiger counters, the Stern-Gerlach experiment and superconducting qubits.