In one minute

Domcke, Garcia-Cely, Lee and Rodd start from a shared signature: inside electromagnetic fields, both axions and gravitational waves induce oscillating magnetic fields. They demonstrate that the size of that response is set largely by the symmetries of the instrument. For low-mass axion haloscopes they derive selection rules giving each detector geometry's sensitivity to axions and gravitational waves, and showing how to shape the experiment to maximise both signals. For a toroidal magnet the best axion and gravitational-wave sensitivities cannot coincide, but changing the pickup loop geometry, or adding several loops, recovers sensitivity to both. The formalism forecasts the best gravitational-wave sensitivity from 100 kHz to 100 MHz for ABRACADABRA, BASE, ADMX SLIC, SHAFT, WISPLC and DMRadio.

Symmetries and selection rules: optimising axion haloscopes for gravitational wave searches