Travelling breather solutions in waveguides for cubic nonlinear Maxwell equations with retarded material laws

Fuente: arXiv
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Main Authors: Ohrem, Sebastian, Reichel, Wolfgang
Format: Preprint
Published: 2025
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author Ohrem, Sebastian
Reichel, Wolfgang
author_facet Ohrem, Sebastian
Reichel, Wolfgang
contents For Maxwell's equations with nonlinear polarization we prove the existence of time-periodic breather solutions travelling along slab or cylindrical waveguides. The solutions are TE-modes which are localized in space directions orthogonal to the direction of propagation. We assume a magnetically inactive and electrically nonlinear material law with a linear $χ^{(1)}$- and a cubic $χ^{(3)}$-contribution to the polarization. The $χ^{(1)}$-contribution may be retarded in time or instantaneous whereas the $χ^{(3)}$-contribution is always assumed to be retarded in time. We consider two different cubic nonlinearities which provide a variational structure under suitable assumptions on the retardation kernels. By choosing a sufficiently small propagation speed along the waveguide the second order formulation of the Maxwell system becomes essentially elliptic for the $\mathbf{E}$-field so that solutions can be constructed by the mountain pass theorem. The compactness issues arising in the variational method are overcome by either the cylindrical geometry itself or by extra assumptions on the linear and nonlinear parts of the polarization in case of the slab geometry. Our approach to breather solutions in the presence of time-retardation is systematic in the sense that we look for general conditions on the Fourier-coefficients in time of the retardation kernels. Our main existence result is complemented by concrete examples of coefficient functions and retardation kernels.
format Preprint
id arxiv_https___arxiv_org_abs_2503_11539
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Travelling breather solutions in waveguides for cubic nonlinear Maxwell equations with retarded material laws
Ohrem, Sebastian
Reichel, Wolfgang
Analysis of PDEs
Primary: 35Q61, 49J10, Secondary: 35C07, 78A50
For Maxwell's equations with nonlinear polarization we prove the existence of time-periodic breather solutions travelling along slab or cylindrical waveguides. The solutions are TE-modes which are localized in space directions orthogonal to the direction of propagation. We assume a magnetically inactive and electrically nonlinear material law with a linear $χ^{(1)}$- and a cubic $χ^{(3)}$-contribution to the polarization. The $χ^{(1)}$-contribution may be retarded in time or instantaneous whereas the $χ^{(3)}$-contribution is always assumed to be retarded in time. We consider two different cubic nonlinearities which provide a variational structure under suitable assumptions on the retardation kernels. By choosing a sufficiently small propagation speed along the waveguide the second order formulation of the Maxwell system becomes essentially elliptic for the $\mathbf{E}$-field so that solutions can be constructed by the mountain pass theorem. The compactness issues arising in the variational method are overcome by either the cylindrical geometry itself or by extra assumptions on the linear and nonlinear parts of the polarization in case of the slab geometry. Our approach to breather solutions in the presence of time-retardation is systematic in the sense that we look for general conditions on the Fourier-coefficients in time of the retardation kernels. Our main existence result is complemented by concrete examples of coefficient functions and retardation kernels.
title Travelling breather solutions in waveguides for cubic nonlinear Maxwell equations with retarded material laws
topic Analysis of PDEs
Primary: 35Q61, 49J10, Secondary: 35C07, 78A50
url https://arxiv.org/abs/2503.11539