Discretization of the Mikhailov model
Song-lin Zhao, Xiao-gang Mu, Da-jun Zhang
TL;DR
This work addresses discretizing the relativistically invariant Mikhailov model by deploying the Cauchy matrix approach. It constructs two discrete Miura transformations and builds the discrete Mikhailov model from two complementary Cauchy matrix schemes, AKNS-type and KP-type, enabling explicit soliton and multiple-pole solutions. The discrete system manifests as a coupled quadrilateral model for variables $(\mu,\nu)$, with a parallel closed form via an alternative variable pair; straight continuum limits recover both the semi-discrete and continuous Mikhailov models along with their Cauchy matrix structures. The methods connect to the negative-order KN hierarchy (AKNS$(-1)$) and self-dual Yang–Mills reductions, suggesting avenues for discretizing related derivative NLS-type systems and exploring Lax integrability and multidimensional consistency in future work.
Abstract
In this paper the Mikhailov model is discretized by means of the Cauchy matrix approach. A pair of discrete Miura transformations are constructed. The discrete Mikhailov model is a coupled system, in which one equation comes from the compatibility of the two Miura transformations, the other is transformed from the discrete negative order Ablowitz-Kaup-Newell-Segur system by using the Miura transformations. Explicit solutions, including solitons and multiple-pole solutions, are presented via two Cauchy matrix schemes respectively, namely, the Ablowitz-Kaup-Newell-Segur type and the Kadomtsev-Petviashvili type. By straight continuum limits, semi-discrete and continuous Mikhailov models together with their Cauchy matrix structures and solutions are recovered.
