Photon Counting Interferometry to Detect Geontropic Space-Time Fluctuations with GQuEST

TL;DR

The paper introduces a novel photon counting interferometer design for the GQuEST experiment, significantly enhancing sensitivity to detect quantum gravity-induced space-time fluctuations in a laboratory setting.

Contribution

It presents a practicable interferometer with a photon counting readout that surpasses the standard quantum limit, enabling faster detection of quantum gravity effects.

Findings

Photon counting readout improves sensitivity beyond the standard quantum limit.

GQuEST can detect quantum gravity phenomena at least 100 times faster.

The design is suitable for laboratory-scale experiments to search for space-time fluctuations.

Abstract

The GQuEST (Gravity from the Quantum Entanglement of Space-Time) experiment uses tabletop-scale Michelson laser interferometers to probe for fluctuations in space-time. We present a practicable interferometer design featuring a novel photon counting readout method that provides unprecedented sensitivity, as it is not subject to the interferometric standard quantum limit. We evaluate the potential of this design to measure space-time fluctuations motivated by recent `geontropic' quantum gravity models. The accelerated accrual of Fisher information offered by the photon counting readout enables GQuEST to detect the predicted quantum gravity phenomena within measurement times at least 100 times shorter than equivalent conventional interferometers. The GQuEST design thus enables a fast and sensitive search for signatures of quantum gravity in a laboratory-scale experiment.