Searching for High Frequency Gravitational Waves with Phonons

With the direct detection of gravitational waves (GWs) from LIGO in 2016, and recent evidence from the NANOGrav collabortion for a stochastic GW background, GW astronomy is becoming an important tool for understanding the universe. Recently it has been shown that axion dark matter (DM) experiments can extend the search for GWs to much higher frequencies, kHz < f < GHz. In this talk we'll discuss how light DM detectors utilizing single phonon excitations in crystal targets, previously shown to be sensitive to a wide variety of DM candidates, are also sensitive to GWs in the frequency range, THz < f < 100 THz, corresponding to the range of optical phonon energies, meV < \omega < 100 meV. We'll discuss the mechanism by which high frequency GWs can generate single phonons, and consider the detector sensitivity of different target materials. Lastly, we'll discuss how these high frequency GWs may be produced in processes such as black hole inspirals and superradiance.