We present a nonlinear partial difference equation defined on a square which is obtained by combining the Miura transformations between the Volterra and the modified Volterra differential-difference equations. This equation is not symmetric with respect to the exchange of the two discrete variables and does not satisfy the 3D-consistency condition necessary to belong to the Adler-Bobenko-Suris classification. Its integrability is proved by constructing its Lax pair.
Squared Eigenfunctions for the Sasa-Satsuma Equation
Squared eigenfunctions are quadratic combinations of Jost functions and adjoint Jost functions which satisfy the linearized equation of an integrable equation. In this article, squared eigenfunctions are derived for the Sasa-Satsuma equation whose spectral operator is a $3\times 3$ system, while its linearized operator is a $2\times 2$ system. It is shown that these squared eigenfunctions are sums of two terms, where each term is a product of a Jost function and an adjoint Jost function. The procedure of this derivation consists of two steps: first is to calculate the variations of the potenti…
In this paper, we explore the integrable fractional derivative nonlinear Schrödinger (fDNLS) equation by using the inverse scattering transform. Firstly, we start from the recursion operator and obtain a formal fDNLS equation. Then the inverse scattering problem is formulated and solved through the matrix Riemann-Hilbert problem. Subsequently, we give the explicit form of the fDNLS equation according to the properties of squared eigenfunctions, such as squared eigenfunctions are the eigenfunctions of the recursion operator of the integrable equations. The reflectionless potential with a simple…
Study of Spectral Statistics of Classically Integrable Systems
在这项工作中,我们提出了一个经典的可积系统,即矩形台球谱统计的研究结果。我们表明,光谱统计确实是泊松的半经典极限几乎所有这样的系统,例外的是非典型的矩形,其两侧的合理平方比,当然能量范围大于L_{\rm max} = \hbar / T_0 $, where $ T_0 $ is the period of the shortest periodic orbit of the system, however $ L_{\rm max} \to \infty $ when $ E \to \infty $。
In this letter, we present a simple and new idea to generate two types of novel integrable multi-Lévy-index and mix-Lévy-index (mixed) fractional nonlinear soliton hierarchies, containing multi-index and mixed fractional higher-order nonlinear Schrödinger (NLS) hierarchy, fractional complex modified Korteweg-de Vries (cmKdV) hierarchy, and fractional mKdV hierarchy. Their explicit forms can be given using the completeness of squared eigenfunctions. Moreover, we present their anomalous dispersion relations via their linearizations, and fractional multi-soliton solutions via the inverse scatteri…