Comparison of Atom Interferometers and Light Interferometers as Space-Based Gravitational Wave Detectors

TL;DR

This paper compares atom and light interferometers for space-based gravitational wave detection, analyzing their sensitivity limits and noise sources, and finds they are similarly limited by phase noise, with atom interferometers having a slight advantage at low frequencies.

Contribution

It provides a detailed comparison of the sensitivity limits of atom and light interferometers, highlighting their similarities and differences in noise mitigation.

Findings

Both interferometers are similarly limited by intrinsic phase noise.

Mitigation strategies like multiple arm configurations are necessary for both.

Atom interferometers have a slight advantage in low-frequency sensitivity due to motion-related noise.

Abstract

We consider a class of proposed gravitational wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, non-inertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g. multiple arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe.