Homogeneous rank one perturbations and inverse square potentials

Following [D,BDG,DR], I describe several exactly solvable families of closed operators. Some of these families are defined by the theory of singular rank one perturbations. The remaining families are Schrodinger operators with inverse square potentials and various boundary conditions. I describe a close relationship between these families. In all of them one can observe interesting renormalization group flows (action of the group of dilations).