Fig. 3: Results of dark photon dark matter search.
From: Long-baseline quantum sensor network as dark matter haloscope
a Distribution of the signal-to-noise ratio of the network-averaged cross-correlation spectrum. The 95% confidence level (C.L.) is determined with Monte Carlo simulation. b Limits on kinetic mixing ϵ of dark photon dark matter in the mass range from 4.1 feV to 2.1 peV. The blue-shaded region is excluded from our network measurement at 95% C.L. The black line shows our future projection of an upgraded magnetometer network. The light-blue shaded regions show other constraints derived from terrestrial or extra-terrestrial experiments, including observing the magnetic fields of Earth33 and Jupiter34, measurements with a network of magnetometers in quiet magnetic environments (SNIPE)59, and Cavendish-Coulomb experiments35. The dashed lines show the limits from cosmological and astrophysical observations, including cosmic microwave background (CMB) photon’s transition to dark photon31,32, and DPDM heating the plasma28,29,30.
