Utilising Atom Interferometers for Dark Matter Detection

Since the internal structure of atoms is possibly sensitive to dark matter (DM), atomic clocks may serve as suitable DM detectors. Additionally, atomic clocks provide a platform for detecting violations of the Einstein equivalence principle (EEP), e. g. universality of clock rates or universality of the gravitational redshift.

These features are not exclusive to atomic clocks, as atom interferometers can detect EEP violations as well, for example via gravimetry. In addition, atomic diffraction processes allow for driving internal transitions, which connects clocks and atom interferometers in a natural fashion.

Making use of the atom interferometer’s internal (clock) transitions allows combining the clock’s and the atom interferometer’s susceptibility to DM in a single apparatus. Furthermore, the atoms’ centre-of-mass motion is potentially affected by DM as well, making atom interferometers susceptible to DM even without internal transitions.

In this contribution we present a unified treatment of clocks and atom interferometers, in which relativistic effects, mass defects, and violation parameters (due to DM and EEP) are included. Based on this formalism, we investigate the leading-order effects for atom interferometers with and without internal transitions, as well as quantum clock interferometry. Consequently, different setups are analysed. Overall, we identify the effects of DM in atom interferometers and discuss the difference between the ones induced by the atom’s clock properties and centre-of-mass effects.