Electromagnetic response produced by interaction of high-frequency gravitational waves from braneworld with galactic-extragalactic magnetic fields

Braneworld scenarios predict very strong high-frequency gravitational waves (HFGWs) in the GHz to THz band. The observation of such HFGWs would provide dynamical evidence for an extra dimension of space. In this paper, we for the first time analytically calculate the electromagnetic (EM) response to HFGWs via the interaction of the HFGWs from the braneworld with the galactic-extragalactic magnetic fields appearing in all galaxies and galaxy clusters, which would give rise to a significant spatial accumulation effect (caused by the synchro-propagation of the HFGWs and perturbed EM waves) and lead to possibly detectable EM signals. Our results show that the power of EM signals at the Earth can theoretically reach ~ 10 super(-21) to ~ 10 super(-5) W with parameters in the typical range expected by contemporary studies and observations (from the lower values for the HFGW amplitude h ~ 10 super(-26) at 10 super(9) Hz and the galactic magnetic field B super((0)) ~ 10 super(-11) T, to the higher values of h ~ 10 super(-22) at 10 super(12) Hz and B super((0)) ~ 10 super(-10) T), and the estimated upper bound of these signals may surpass the minimum level detectable by current technology.