Gravito-electromagnetic resonances in Minkowski space

Abstract: We consider the interaction between gravitational and electromagnetic radiation propagating on a Minkowski background and look into the effects of the former upon the latter. Not surprisingly, the coupling between these two sources leads to gravitationally driven electromagnetic waves. At the second perturbative level, the driving force appears as the superposition of two waves, the properties of which are decided by the initial conditions. We find that the Weyl-Maxwell interaction typically leads to electromagnetic beat-like signals and, in some cases, to the resonant amplification of the driven electromagnetic wave. For physically reasonable initial conditions, we show that these resonances imply a linear (in time) growth for the amplitude of the electromagnetic signal, with the overall amplification also depending on the strength of the driving gravity wave. Finally, we provide order-of-magnitude estimates of the achieved amplification by applying our analysis to astrophysical environments where both gravitational and electromagnetic waves are expected to coexist.