Generic appearance of objective results in quantum measurements

TL;DR

This paper demonstrates that objective, classical-like results naturally emerge in quantum measurements through coarse-graining and time evolution, using a model-independent approach and random matrix theory.

Contribution

It provides a universal, model-independent analysis showing how objective measurement outcomes arise in quantum mechanics, with explicit timescales derived from system parameters.

Findings

Objective results emerge after coarse-graining and sufficient waiting time.

Universal objectivization timescales depend on interaction strength and system size.

Results are validated using random matrix theory and Hoeffding inequality.

Abstract

Measurement is of central interest in quantum mechanics as it provides the link between the quantum world and the world of everyday experience. One of the features of the latter is its robust, objective character, contrasting the delicate nature of quantum systems. Here we analyze in a completely model-independent way the celebrated von Neumann measurement process, using recent techniques of information flow, studied in open quantum systems. We show the generic appearance of objective results in quantum measurements, provided we macroscopically coarse-grain the measuring apparatus and wait long enough. To study genericity, we employ the widely-used Gaussian Unitary Ensemble of random matrices and the Hoeffding inequality. We derive generic objectivization timescales, given solely by the interaction strength and the systems' dimensions. Our results are manifestly universal and are a generic property of von Neumann measurements.