Decoherence, quantum Darwinism, and the generic emergence of our objective classical reality

TL;DR

This paper explains how decoherence and quantum Darwinism account for the emergence of classical reality from quantum mechanics, addressing the preferred basis problem and the measurement problem with generic, scalable results.

Contribution

It introduces a framework showing that classicality naturally emerges from quantum mechanics' mathematical structure, moving beyond specific models to more general, scalable insights.

Findings

Decoherence explains why macroscopic superpositions are not observed.

Quantum Darwinism accounts for the emergence of objective classical states.

Results demonstrate classicality as a generic phenomenon from quantum structure.

Abstract

In this article I aim to provide an intuitive and non-technical introduction to decoherence and quantum Darwinism. Together these theories explain how our classical reality emerges from an underlying quantum mechanical description. Here I focus on two aspects of this and explain, firstly, how decoherence can tell us why we never see macroscopic superpositions, such as dead-and-alive cats, in our classical surroundings; and secondly I describe and then provide a resolution to the so-called preferred basis problem. I then introduce recent results demonstrating that certain aspects of classicality are generic phenomena that emerge from the basic mathematical structure of quantum mechanics. This is in stark contrast to previous work in this field that focused on specific models that cannot realistically be scaled up to explicitly answer questions about the macroscopic world. Finally, I demonstrate how decoherence and quantum Darwinism can shed significant light on the measurement problem, and I discuss the implications for how we should interpret quantum mechanics.