Sucai Niu | Searcharxiv

arXiv2025

Well-posedness to nonlinear Schr\"odinger-Gerdjikov-Ivanon equation

The Riemann-Hilbert approach is extended to discuss the well-posedness of the nonlinear Schr\"odinger-Gerdjikov-Ivanon equation. The Lipschitz continuity of potential in $H^{2}(\mathbb{R})\cap H^{1,1}(\mathbb{R})$ to scattering data is obtained through direct scattering transform. Two Riemann-Hilbert problems are constructed, and two sets of the reflection coefficients, that is $r(k)$ and $r_\pm(z)$, are introduced. The Lipschitz continuity from the reflection coefficients $r_\pm(z)$ in $H^{1}(\mathbb{R})\cap L^{2,1}(\mathbb{R})$ to the potential is estimated via the potential reconstruction. Existence of global solutions of NLS-GI equation is considered by the Riemann-Hilbert problem without eigenvalues or resonances.

math.AP↗

arXiv2025

Existence of global solutions to the massive Thirring model in the non-laboratory coordinates

The massive Thirring model in the non-laboratory coordinates is considered by the Riemann-Hilbert approach. Existence of global solutions is shown for the cases of the associated Riemann-Hilbert problem without eigenvalues or resonances. The Lipschitz continuity of the map from the potential $v_0(x)\in H^2(\mathbb{R})\cap H^{1,1}(\mathbb{R})$ to the scattering data is given in the direct scattering transform. Two transform matrices are introduced to curb the convergence of the Volterra integral equations and the relevant estimates of the modified Jost functions. For small potential, the solvability of the Riemann-Hilbert problems without eigenvalues or resonances is discussed. The Lipschitz continuity of the map from the scattering data to the potential $v(x)$ is shown. The reconstructions for potential $u(x,t)$ and $v(x,t)$ are finished by considering the time dependence of the scattering data and by constructing the conservation laws obtain via the dressing method.

math-ph↗