Integrable nonlinear lattice associated with the third-order spectral problem
Abstract:
We propose a nonlinear model on a regular infinite one-dimensional
lattice. It describes the three component dynamical system with modulated
on-site masses and is shown to admit a zero-curvature representation. The
associated auxiliary spectral problem is basically of third order
and gives rise to fairly complicated subdivision
into domains of regularity of Jost functions in the plane of complex
spectral parameter. As a result, both the direct and the inverse scattering
problems turn out to be
substantially nontrivial. The Caudrey version of the direct and inverse
scattering technique for the needs of model integration is adapted. The
simplest soliton solution is found.