Maxwell wave packets in de Sitter expanding universe

Abstract

AbstractWe study for the first time the propagation of the packets of plane waves of the Maxwell free field in the de Sitter expanding universe as detected by an observer staying at rest in his proper frame with physical de Sitter–Painlevé coordinates. This observes an accelerate propagation of the wave packet along to a null geodesic, laying out a severe exponential decay and a moderate dispersion, increasing exponentially in time during propagation. The example we give is the usual anisotropic Gaussian packet for which we present a short graphical analysis pointing out the accelerated propagation, decay and dispersion. Moreover, we show that the observer perceives his horizon as a mirror stopping the wave packets prepared on it and reflecting those prepared beyond it.