A Kilometre-Baseline Atom-Interferometer Network for the Mid-Frequency Gravitational-Wave Band: Strain Sensitivity Computed from Phase Noise

A terrestrial detector network based on atom interferometry is designed for the gravitational-wave band between the reach of ground laser interferometers and space missions. A vertical baseline of 1 km, large-momentum-transfer optics of 1,000 photon recoils (effective wavenumber 8.06e+09 per metre) and a shot-noise phase sensitivity of 1e-4 radians per shot give a computed strain sensitivity of 1.24e-17 per root hertz near 1 Hz for one gradiometer. Three such sites form the network. Each site is estimated at 1,400 tonnes and 750 kW. All figures are computed from the stated phase-noise model; the design is simulated, not measured.