ALP Seminar: The search for high frequency gravitational waves with resonant cavities

Abstract: The observations of gravitational waves in the Hz - kHz frequency range by the interferometers LIGO-Virgo started the era of gravitational waves (GWs) astronomy. A huge effort of research is currently performed to extend the range of observed frequencies. In this context, it appeared that GWs in the GHz range might be searched thanks to resonant cavities using the so-called inverse Gertsensthein effect. The basic idea behind this phenomenon is that a gravitational wave propagating through a static electromagnetic field sources an effective electromagnetic current oscillating at the gravitational wave frequency. In this presentation, we will follow, in a pedagogical way, the different steps that bring the physicist from GW physics to an expression for the observed signal in the resonant cavity. We will also discuss possible sources for such signals, focusing on black hole mergers.