Probing GHz gravitational waves with graviton-magnon resonance

A novel method for extending the frequency frontier in gravitational wave observations is proposed. It is shown that gravitational waves can excite a magnon. Thus, gravitational waves can be probed by a graviton-magnon detector which measures resonance fluorescence of magnons. Searching for gravitational waves with a wave length lambda by using a ferromagnetic sample with a dimension l, the sensitivity of the graviton-magnon detector reaches spectral densities, around 5.4x10-22x(mml:mfrac lambda 2 pi mml:mfrac)-2mml:mspace width=4ptmml:mspace[Hz-1/2] at 14 GHz and 8.6x10-21x(mml:mfracl lambda /2 pi mml:mfrac)-2mml:mspace width=4ptmml:mspace>[Hz-1/2] at 8.2 GHz, respectively.