DESY Theory Seminar

Hunting for Light DM with Quantum Sensors

by Clara Murgui (Caltech)




Direct detection experiments search for dark matter through its potential interactions with the SM particles. However, light dark matter models with particle masses below the GeV scale are still largely unconstrained. As we will see in this talk, sensitivity to such small momentum transfer can benefit from quantum sensors, which employ fundamental quantum mechanical phenomena to notice energy depositions otherwise unreachable. Quantum sensors can considerably extend the range in dark matter mass of traditional WIMP experiments and be complementary to other direct detection methods. In the first part of the talk, I will examine a proposal to use atom interferometers to detect a light dark matter subcomponent at sub-GeV masses. The detection principle is based on the fact that DM scattering off of one “arm” of the atom interferometer can cause trackable decoherence and phase shifts. Two key factors render atom interferometers highly competitive experiments for very low masses: they are sensitive to extremely low momentum deposition and their coherent atoms give them a boost in sensitivity. On the second part of the talk, I will present a novel proposal (ongoing work) to search for the QCD axion with optomechanical cavities. As we will see, the population of coherent phonons that such cavities can host is crucial to overcome the suppression coming from the QCD axion-photon coupling. A unique advantage of this new strategy, axioptomechanics, is that the cavity size need no longer be matched to the axion mass.