Observer Dependence in Consistent Histories and General Relativity

TL;DR

This paper explores observer dependence in quantum mechanics and general relativity, developing a theory of observers within GR that reveals classical CHSH inequalities can be violated in curved spacetime.

Contribution

It introduces a framework linking consistent histories in quantum mechanics with observer theory in GR, and shows classical CHSH violations occur on curved backgrounds.

Findings

CHSH inequality can be violated by classical theories in curved spacetime

Framework reveals mathematical similarities between observer dependence in GR and consistent histories

Classical theories may exhibit quantum-like violations in curved backgrounds

Abstract

Observer dependence is central to Quantum Mechanics; in particular if we associate consistent sets with observer worldviews we can think of the Consistent Histories (CH) interpretation as a formalisation of observer dependence. However we lack a theory of the observers themselves. In this paper we begin by building such a theory within General Relativity (GR), and find that this framework bears close mathematical resemblance to the treatment of consistent sets in CH. We therefore adapt the CHSH framework to identify the `gap' between the classical and quantum theories. We find that the CHSH argument does not hold on a curved background, so that the inequality may be violated by classical theories.