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

Atom interferometers (AIs) as gravitational-wave (GW) detectors have been pro-posed 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 cos-mology. 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 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 H0 with a precision 2.1%, which is sufficient to arbitrate the Hub-ble 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.

Automated summary

This study investigates the potential of space-borne atom interferometers (AIs) as gravitational-wave (GW) detectors and their applications in cosmology. Using AEDGE as the fiducial AI GW detector, it is found that around 30 bright sirens can be obtained within a five-year period, allowing for measurements of H0 and improvements in the equation of state of dark energy. Additionally, modifications in GW propagation on cosmological scales can constrain deviations from general relativity at a precision level of 5.7%.