Space-borne atom interferometric gravitational wave detections. Part I. The forecast of bright sirens on cosmology

TL;DR

This paper explores the potential of space-borne atom interferometers, specifically AEDGE, to detect gravitational wave standard sirens for cosmology, estimating their impact on measuring the Hubble constant, dark energy, and modified gravity.

Contribution

It is the first study to evaluate the use of space-borne atom interferometers for detecting bright GW sirens and their application in constraining cosmological parameters.

Findings

Approximately 30 bright sirens can be detected in 5 years with AEDGE.

Bright sirens can measure H_0 with 2.1% precision, addressing the Hubble tension.

Inclusion of bright sirens marginally improves dark energy equation of state measurements.

Abstract

Atom interferometers (AIs) as gravitational-wave (GW) detectors have been proposed a decade ago. Both ground and space-based projects will be in construction and preparation in the near future. In this paper, for the first time, we investigate the potential of the space-borne AIs on detecting GW standard sirens and hence the applications on cosmology. We consider AEDGE as our fiducial AI GW detector and estimate the number of bright sirens that would be obtained within a 5-years data-taking period of GW and with the follow-up observation of electromagnetic (EM) counterparts. We then construct the mock catalogue of bright sirens and predict their ability on constraining cosmological parameters such as the Hubble constant, dynamics of dark energy, and modified gravity theory. Our preliminary results show around order $\mathcal{O} (30)$ bright sirens can be obtained from a 5-years operation time of AEDGE and the follow-up observation of EM counterparts. The bright sirens alone can measure $H_0$ with a precision of 2.1\%, which is sufficient to arbitrate the Hubble tension. Combining current most precise electromagnetic experiments, the inclusion of AEDGE bright sirens can improve the measurement of the equation of state of dark energy, though marginally. Moreover, by modifying GW propagation on cosmological scales, the deviations from general relativity (modified gravity theory effects) can be constrained at 5.7\% precision level.