Singular Dirac systems and Sturm-Liouville problems nonlinear in the spectral parameter
Here, the Dirac operator \[ H=-i\alpha \nabla +\beta+V \] acting in \(L^2(\mathbb{R}^3)^4\) with a spherically symmetric potential \(V\) is studied. Under certain additional assumptions on \(V\), the essential spectrum satisfies \(\sigma_{ess}(H)= \mathbb{R}\backslash (-1,1)\). The authors investigate whether the endpoints \(-1\) and \(1\) of the gap \((-1,1)\) are accumulation points of discrete eigenvalues.
scientific article; zbMATH DE number 1797551