Accumulation of complex eigenvalues of an indefinite Sturm--Liouville operator with a shifted Coulomb potential

Michael Levitin, Marcello Seri

For a particular family of long-range potentials $V$, we prove that the eigenvalues of the indefinite Sturm--Liouville operator $A=\mathrm{sign}(x)(-\Delta +V(x))$ accumulate to zero…