This paper is devoted to a general min-max characterization of the eigenvalues in a gap of the essential spectrum of a self-adjoint unbounded operator. We prove an abstract theorem, then we apply it to the case of Dirac operators with a Coulomb-like potential. The result is optimal for the Coulomb potential.
@article{hal-00659883,
author = {Dolbeault, Jean and Esteban, Maria J. and S\'er\'e, Eric},
title = {On the eigenvalues of operators with gaps. Application to Dirac operators.},
journal = {HAL},
volume = {2000},
number = {0},
year = {2000},
language = {en},
url = {http://dml.mathdoc.fr/item/hal-00659883}
}
Dolbeault, Jean; Esteban, Maria J.; Séré, Eric. On the eigenvalues of operators with gaps. Application to Dirac operators.. HAL, Tome 2000 (2000) no. 0, . http://gdmltest.u-ga.fr/item/hal-00659883/