Stability of solitary waves in nonlinear Klein-Gordon equations

The stability of topological solitary waves and pulses in one-dimensional nonlinear Klein–Gordon systems is revisited. The linearized equation describing small deviations around the static solution leads to a Sturm–Liouville problem, which is solved in a systematic way for the -l(l+1)sech2(x), showi...

Descripción completa

Detalles Bibliográficos
Autores: Rabán Mondéjar, Pablo, Álvarez Nodarse, Renato, Quintero, Niurka R.
Tipo de recurso: artículo
Estado:Versión enviada para evaluación y publicación
Fecha de publicación:2022
País:España
Institución:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/140576
Acceso en línea:https://hdl.handle.net/11441/140576
https://doi.org/10.1088/1751-8121/aca0d1
Access Level:acceso abierto
Palabra clave:Nonlinear Klein–Gordon equations
Sturm–Liouville problem
Stability
Kink solution
Descripción
Sumario:The stability of topological solitary waves and pulses in one-dimensional nonlinear Klein–Gordon systems is revisited. The linearized equation describing small deviations around the static solution leads to a Sturm–Liouville problem, which is solved in a systematic way for the -l(l+1)sech2(x), showing the orthogonality and completeness relations fulfilled by the set of its solutions for all values l Ɛ N. This approach enables the linear stability of kinks and pulses of certain nonlinear Klein–Gordon equations to be determined. The inverse problem, which starts from Sturm–Liouville problem and obtains nonlinear Klein–Gordon potentials, is also revisited and solved in a direct way. The exact solutions (kinks and pulses) for these potentials are calculated, even when the nonlinear potential is not explicitly known. The kinks are found to be stable, whereas the pulses are unstable. The stability of the pulses is achieved by introducing certain spatial inhomogeneities.