On Schrödinger operators with multipolar inverse-square potentials ✩

Positivity, essential self-adjointness, and spectral properties of a class of Schrödinger operators with multipolar inverse-square potentials are discussed. In particular a necessary and sufficient condition on the masses of singularities for the existence of at least a configuration of poles ensuring the positivity of the associated quadratic form is established. © 2007 Elsevier Inc. All rights reserved