Energy backflow in unidirectional spatiotemporally localized wavepackets
Abstract
Backflow, or retro-propagation, is a counterintuitive phenomenon where for a forward-propagating wave the energy or probability density locally propagates backward. In this study the energy backflow has been examined in connection with relatively simple causal unidirectional finite-energy solutions of the wave equation which are derived from a factorization of the so-called basic splash mode. Specific results are given for the energy backflow arising in known azimuthally symmetric unidirectional wavepackets, as well as in novel azimuthally asymmetric extensions. Using the Bateman-Whittaker technique, a novel finite-energy unidirectional null localized wave has been constructed that is devoid of energy backflow and has some of the topological properties of the basic Hopfion.
Keywords
Cite
@article{arxiv.2208.08251,
title = {Energy backflow in unidirectional spatiotemporally localized wavepackets},
author = {Ioannis Besieris and Peeter Saari},
journal= {arXiv preprint arXiv:2208.08251},
year = {2023}
}
Comments
10 pages, 8 figures. In comparison with v1, some refs. to arXiv have been updated by journal ones, some paragraphs in Introduction revised and a remark about possible experimental verification added to Conclusions