Thomson scattering induced by gravitational waves

Abstract

We investigate the effects of a weak gravitational wave, modelled as a gaussian wavepacket, on the polarization state of an electromagnetic field enclosed in a cavity. Our approach is semiclassical, in that the electromagnetic field is described as a quantum field, while the gravitational perturbation is treated classically, as a slightly curved background spacetime. Assuming that before the interaction the electromagnetic field has been prepared in a given polarization state, we show that -due to the gravitational scattering with the wave -some photons having different polarization states are found in the cavity at late times. Such polarization scattering has some resemblance with Thomson scattering, well-known in Quantum Electrodynamics: hence the motivation for the title. We give a numerical estimate of the resulting photon polarization spreading in the case of a typical gravitational burst from a final supernova rebound. We also briefly comment about the possible influence of such gravitational scattering on the Cosmic Microwave Background (CMB) polarization.

Phonon creation by gravitational waves

“…r The fact that gravitational waves can generate photons in fields confined in certain regions of spacetime was pointed out in [30,31]. However, the effect is negligible in optical cavities since gravitational waves typically have frequencies several orders of magnitude below the optical regime.…”

Gravitational waves and coherent phonon states in elastic media: 1D-analysis

“…Coupling between superconductors and gravitational waves has been studied in [8][9][10]. Also, influence of electromagnetic, gravitational and gravitoelectromagnetic waves on superconductors has been investigated in [11][12][13][14][15][16][17][18][19][20]. In recent years some Authors have considered the behaviour of Bose-Einstein condensates (BEC) in presence of weak gravitational waves, discussing possible phonon excitation inside the condensate [21,22] as an example of gravitationally induced particle creation [23].…”