Gravitational Decoherence: A Thematic Overview

TL;DR

This paper reviews gravitational decoherence, examining theories based on general relativity and quantum field theory, and discusses how future space experiments could test these theories and clarify gravity's fundamental nature.

Contribution

It provides a comprehensive overview of gravitational decoherence models rooted in GR and QFT, and analyzes their experimental implications and theoretical differences.

Findings

Different GD models predict distinct experimental signatures.

Space-based experiments can discriminate between quantum and non-GR theories.

Future experiments may determine if gravity is fundamental or effective.

Abstract

Gravitational decoherence (GD) refers to the effects of gravity in actuating the classical appearance of a quantum system. Because the underlying processes involve issues in general relativity (GR), quantum field theory (QFT) and quantum information, GD has fundamental theoretical significance. There is a great variety of GD models, many of them involving physics that diverge from GR and/or QFT. This overview has two specific goals along one central theme: (i) present theories of GD based on GR and QFT and explore their experimental predictions; (ii) place other theories of GD under the scrutiny of GR and QFT, and point out their theoretical differences. We also describe how GD experiments in space in the coming decades can provide evidences at two levels: a) discriminate alternative quantum theories and non-GR theories; b) discern whether gravity is a fundamental or an effective theory.