Wave-Medium Interactions in Dynamic Matter and Modulation Systems

TL;DR

This paper explores wave interactions with dynamic media and modulation systems, revealing unique energy-momentum exchange effects and the significance of the catch-up phenomenon in non-moving matter systems.

Contribution

It provides new formulations for wave-medium interactions in modulation systems, highlighting differences from traditional moving-matter systems and analyzing Fresnel-Fizeau drag effects.

Findings

Catch-up effect influences wave-interface interactions.

Distinct energy-momentum exchanges in modulation systems.

Reveals Fresnel-Fizeau drag effects in dynamic media.

Abstract

Space-time modulation systems have garnered significant attention due to their resemblance to moving-matter systems and promising applications. Unlike conventional moving-matter systems, modulation systems do not involve net motion of matter, and are therefore easier to implement and not restricted to subluminal velocities. However, canonical wave-medium interaction aspects, such as scattering and energy-momentum relations, have remained largely unexplored. In this paper, we address the aforementioned issues for three dynamic systems: moving-matter blocs, moving-perturbation interfaces and moving-perturbation periodic structures, and provide corresponding general formulations along with comparisons. Our investigation reveals the significant roles played by the "catch-up" effect between waves and interfaces. Even more interestingly, it reveals different energy and momentum exchanges between moving media and homogenized moving-perturbation structures as a result of conventional and reverse Fresnel-Fizeau drag effects.