Exploring the depths of symmetry in the mKdV equation: physical interpretations and multi-wave solutions

TL;DR

This paper investigates the infinite symmetries of the mKdV equation, explores their physical meanings, and uses these symmetries to derive various exact multi-wave solutions like solitons and breathers.

Contribution

It introduces a symmetry conjecture for the mKdV equation and demonstrates how to derive complex multi-wave solutions using symmetry constraints.

Findings

Symmetries can be decomposed into translations and wave number shifts.

The symmetry conjecture is supported by soliton solution analysis.

Exact multi-wave solutions are obtained via symmetry constraints.

Abstract

This manuscript embarks on an in-depth exploration of the modified Korteweg-de Vries (mKdV) equation, with a particular emphasis on unraveling the intricate structure of its infinite symmetries and their physical interpretations. Central to this investigation are the $K$-symmetries and $\tau$-symmetries, which are delineated by a recursive relationship and constitute an infinite ensemble that underpins the conservation laws. We engage with an existing symmetry conjecture, which posits that the currently identified symmetries represent a subset of a more expansive, yet to be unearthed, set. This conjecture is substantiated through an analysis of the soliton solutions associated with the mKdV equation, demonstrating that these symmetries can be decomposed into linear combinations of center and wave number translation symmetries. Further, by imposing an infinite sequence of symmetry constraints, it becomes feasible to derive exact multi-wave solutions. This methodology, predicated on the proposed symmetry conjecture, facilitates the extraction of exact solutions, encompassing complexiton, breather, multi-soliton solutions, among others.