Detecting cosmological scalar fields using orbital networks of quantum sensors

In this paper, we propose a method to detect the interaction of a hypothetical coherently evolving cosmological scalar field with an orbital network of quantum sensors, focusing on the Global Positioning System (GPS) satellite network as a test example. Cosmological scenarios, such as a scalar-tensor theory for dark energy or the axi-Higgs model, suggest that such a field may exist. As this field would be (approximately) at rest in the cosmic microwave background (CMB) frame, it would exhibit a dipole as a result of the movement of our terrestrial observers relative to the CMB. While the current sensitivity of the GPS network is insufficient to detect a cosmological dipole, future networks of quantum sensors on heliocentric orbits, using state-of-the-art atomic clocks, can reach and exceed this requirement.