Conjugate atom interferometry for gravitational-wave detection
Phys. Rev. D 114, 042004 – Published 28 August, 2026
DOI: https://doi.org/10.1103/jbb7-9z7c
Abstract
The midfrequency gravitational-wave window remains largely uncovered, and atom interferometry with phase-accumulating large momentum transfer is a promising candidate to fill this gap. However, in previously proposed two-photon schemes, placing atomic ensembles on separate satellites breaks common-mode laser phase noise cancellation, creating a persistent dilemma between signal amplification and noise immunity. We resolve this trade-off with a differential dual-atom-interferometer architecture whose physical layout differs fundamentally from earlier designs. Two conjugate atom interferometers are collocated on a single platform, forming the hub of a three-satellite Michelson configuration, rather than being placed on separate satellites. This structural change enables a distinct measurement scheme in which cascaded composite Bragg pulses amplify the signal coherently, while the differential readout between the two collocated interferometers suppresses common-mode laser phase noise. To the best of our knowledge, this design is the first two-photon scheme to achieve high signal amplification and robust laser phase noise rejection simultaneously. It also provides the first quantum coherent phase accumulation and readout module based on differential measurement that can be directly integrated into existing laser interferometric observatories, such as Laser Interferometer Space Antenna and TianQin, enabling a hybrid multiband gravitational-wave detector.