A Measure of Classicality

TL;DR

This paper introduces a measure to quantify the classicality of quasiclassical realms emerging from quantum mechanics, exploring how different classical features influence information systems and the observable universe.

Contribution

It proposes a novel measure of classicality for quasiclassical realms and discusses its implications for observers and information gathering in the universe.

Findings

Different quasiclassical realms can be characterized by various variables and levels of classicality.

The measure of classicality can help understand the emergence of classical physics from quantum foundations.

Implications for information gathering systems and observers are considered.

Abstract

A striking feature of our fundamentally indeterministic quantum universe is its quasiclassical realm -- the wide range of time place and scale in which the deterministic laws of classical physics hold. Our quasiclassical realmis an emergent feature of the fundamental theories of our universe's quantum state and dynamics. There are many types of quasiclassical realms our Universe could exhibit characterized by different variables, different levels of coarse-graining, different locations in spacetime, different classical physics, and different levels of classicality.We propose a measure of classicality for quasiclassical realms, We speculate on the observable consequences of different levels of classicality especially for information gathering and utilizing systems (IGUSes) such ourselves as observers of the Universe.