Melina Filzinger, Ashlee R. Caddell, Dhruv Jani, Martin Steinel, Leonardo Giani, Nils Huntemann, and Benjamin M. Roberts, arXiv:2312.13723
We devise and demonstrate a method to search for non-gravitational couplings of ultralight dark matter to standard model particles using space-time separated atomic clocks and cavity-stabilized lasers. By making use of space-time separated sensors, which probe different values of an oscillating dark matter field, we can search for couplings that cancel in typical local experiments. We demonstrate this method using existing data from a frequency comparison of lasers stabilized to two optical cavities connected via a 2220 km fiber link [Nat. Commun. 13, 212 (2022)]. The absence of significant oscillations in the data results in constraints on the coupling of scalar dark matter to electrons, \(d_{m_e}\), for masses between \(10^{-19}\) eV and \(2\times10^{-15}\) eV. These are the first constraints on \(d_{m_e}\) alone in this mass range, and improve the dark matter constraints on any scalar-Fermion coupling by up to two orders of magnitude.
