Von NeumannWigner theorem: Level repulsion and degenerate eigenvalues
Abstract
We investigate the spectral properties of Schrödinger operators with point interactions, focusing attention on the interplay between level repulsion (von NeumannWigner theorem) and the symmetry of the confi.guration of point interactions. The explicit solution of the problem allows observing level repulsion for two centers. For a large number of centers, we investigate the families of point interactions leading to the maximum degeneracy.
 Publication:

Theoretical and Mathematical Physics
 Pub Date:
 October 2007
 DOI:
 10.1007/s112320070124y
 Bibcode:
 2007TMP...153.1407D
 Keywords:

 von NeumannWigner theorem;
 zerorange potential;
 extension theory;
 inverse spectral problem