- Oct. 25, 2021, 2:00 pm US/Central
Speaker: Asimina Arvanitaki, Perimeter Institute
Abstract: Axion dark matter (DM) constitutes an oscillating P- and T-violating background. Inside piezoelectric crystals, which break parity spontaneously, this axion background can result in a stress. We call this new phenomenon “the piezoaxionic effect”. When the frequency of axion DM matches the natural frequency of a bulk acoustic normal mode of the piezoelectric crystal, the piezoaxionic effect is resonantly enhanced and can be read out electrically via the piezoelectric effect. We explore all axion couplings that can give rise to the piezoaxionic effect, the most promising being the defining coupling of the QCD axion through the anomaly in the strong sector. We also point out another, subdominant, new phenomenon that is present in all dielectrics, namely “the electroaxionic effect”. When the nuclear or electron spins are aligned inside a crystal, an axion background will induce an oscillating electric dipole moment (EDM) density that gives rise to a voltage across the crystal. The electroaxionic effect is again present for all axion couplings, but is largest for the axion coupling to the QCD anomaly. We find that this model-independent coupling of the QCD axion may be probed through the combination of the piezoaxionic and electroaxionic effects in piezoelectric crystals, with near-future experimental setups applicable for axion masses between 10^-11 eV and 10^-7 eV, a challenging range for most other detection concepts.