Quantum-information methods for quantum gravity laboratory-based tests

TL;DR

This paper reviews the emerging use of quantum information-theoretic methods to design laboratory tests for quantum gravity, focusing on gravitational entanglement detection between quantum probes and its implications for unifying quantum theory and gravity.

Contribution

It introduces and discusses the application of information-theoretic approaches to quantum gravity testing, highlighting experimental proposals and their potential to reveal quantum gravitational effects.

Findings

Detection of gravitational entanglement between quantum probes

Comparison of multi-probe and single-probe schemes

Potential implications for quantum gravity theories

Abstract

Quantum theory and general relativity are about one century old. At present, they are considered the best available explanations of physical reality, and they have been so far corroborated by all experiments realised so far. Nonetheless, the quest to unify them is still ongoing, with several yet untested proposals for a theory of quantum gravity. Here we review the nascent field of information-theoretic methods applied to designing tests of quantum gravity in the laboratory. This field emerges from the fruitful extension of quantum information theory methodologies beyond the domain of applicability of quantum theory itself, to cover gravity. We shall focus mainly on the detection of gravitational entanglement between two quantum probes, comparing this method with single-probe schemes. We shall review the experimental proposal that has originated this field, as well as its variants, their applications, and discuss their potential implications for the quantum theory of gravity. We shall also highlight the role of general information-theoretic principles in illuminating the search for quantum effects in gravity.