Asymptotics of the Hartree-type operator spectrum near the lower boundaries of spectral clusters
We consider the eigenvalue problem for a perturbed two-dimensional
resonance oscillator. The excitation potential is given by a Hartree-type
nonlinearity with a smooth self-action potential. We use asymptotic
formulas for the quantum averages to obtain asymptotic eigenvalues and
asymptotic eigenfunctions near the lower boundaries of spectral clusters
which are formed near the energy levels of the unperturbed operator.