Transient propagation: An explanation for superluminal phenomena

Abstract

Based on an established rigorous solution for transient propagation of electromagnetic waves, an explanation for superluminal phenomena is proposed. Faster-than-light traveling appears an illusion due to group reshaping. The rigor of the transient propagation ensures that the Einstein causality remains intact for individual waves. The intensity transient propagation increases to a peak before decaying into the stationary propagation. A group of waves (e.g. Gaussian light pulse) may be reshaped near the peak region. When the propagation is heavily attenuated and the pulse extents to the transient peak while its center remains before the interface, the enhanced transient peak may be interpreted as the pulse center, and the propagation appears superluminal. The reshaped pulse appears accelerated when observed before the transient peak, whereas the reshaped pulse appears decelerated when observed after the transient peak.