Transient waves in linear dispersive media with dissipation: an approach based on the steepest descent path

Fuente: arXiv
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Main Authors: Mainardi, Francesco, Mentrelli, Andrea, Santander, Juan Luis Gonza'les
Format: Preprint
Published: 2025
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author Mainardi, Francesco
Mentrelli, Andrea
Santander, Juan Luis Gonza'les
author_facet Mainardi, Francesco
Mentrelli, Andrea
Santander, Juan Luis Gonza'les
contents In the study of linear dispersive media it is of primary interest to gain knowledge of the impulse response of the material. The standard approach to compute the response involves a Laplace transform inversion, i.e., the solution of a Bromwich integral, which can be a notoriously troublesome problem. In this paper we propose a novel approach to the calculation of the impulse response, based on the well assessed method of the steepest descent path, which results in the replacement of the Bromwich integral with a real line integral along the steepest descent path. In this exploratory investigation, the method is explained and applied to the case study of the Klein- Gordon equation with dissipation, for which analytical solutions of the Bromwich integral are available, as to compare the numerical solutions obtained by the newly proposed method to exact ones. Since the newly proposed method, at its core, consists in replacing a Laplace transform inverse with a potentially much less demanding real line integral, the method presented here could be of general interest in the study of linear dispersive waves in presence of dissipation, as well as in other fields in which Laplace transform inversion come into play.
format Preprint
id arxiv_https___arxiv_org_abs_2511_00045
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Transient waves in linear dispersive media with dissipation: an approach based on the steepest descent path
Mainardi, Francesco
Mentrelli, Andrea
Santander, Juan Luis Gonza'les
General Mathematics
41A60, 30E15, 44A10, 35L20, 33C10
In the study of linear dispersive media it is of primary interest to gain knowledge of the impulse response of the material. The standard approach to compute the response involves a Laplace transform inversion, i.e., the solution of a Bromwich integral, which can be a notoriously troublesome problem. In this paper we propose a novel approach to the calculation of the impulse response, based on the well assessed method of the steepest descent path, which results in the replacement of the Bromwich integral with a real line integral along the steepest descent path. In this exploratory investigation, the method is explained and applied to the case study of the Klein- Gordon equation with dissipation, for which analytical solutions of the Bromwich integral are available, as to compare the numerical solutions obtained by the newly proposed method to exact ones. Since the newly proposed method, at its core, consists in replacing a Laplace transform inverse with a potentially much less demanding real line integral, the method presented here could be of general interest in the study of linear dispersive waves in presence of dissipation, as well as in other fields in which Laplace transform inversion come into play.
title Transient waves in linear dispersive media with dissipation: an approach based on the steepest descent path
topic General Mathematics
41A60, 30E15, 44A10, 35L20, 33C10
url https://arxiv.org/abs/2511.00045