Role of atoms in atomic gravitational-wave detectors

TL;DR

This paper compares atomic clock and atom interferometer gravitational-wave detectors, proposing enhancements for confined atoms to improve sensitivity and coherence time, advancing space-based gravitational-wave detection technology.

Contribution

It introduces a unified framework for clock and atom interferometer detectors and proposes novel enhancements for confined atoms to boost sensitivity and coherence.

Findings

Unified sensitivity mechanism for clocks and interferometers

Proposed enhancements for confined atoms to improve detector performance

Extended coherence time beyond atomic excited state lifetime

Abstract

Recently, it has been proposed that space-based atomic sensors may be used to detect gravitational waves. These proposals describe the sensors either as clocks or as atom interferometers. Here, we seek to explore the fundamental similarities and differences between the two types of proposals. We present a framework in which the fundamental mechanism for sensitivity is identical for clock and atom interferometer proposals, with the key difference being whether or not the atoms are tightly confined by an external potential. With this interpretation in mind, we propose two major enhancements to detectors using confined atoms, which allow for an enhanced sensitivity analogous to large-momentum-transfer (LMT) used in atom interferometry (though with no transfer of momentum to the atoms), and a way to extend the useful coherence time of the sensor beyond the atom's excited state lifetime.