Abstract
I will analyse self-adjoint operators on the bosonic Fock space
defined as quadratic polynomials in creation/annihilation operators.
I will show that there exists 9 distinct classes of such operators
exhibiting various behavior in the infra-red and ultra-violet regime.
I will describe their scattering theory, which is quite unusual (from the
point of view of people accustomed to Schrodinger operators). The analysis
of these operators is helpful in understanding various phenomena in
quantum field theory
Contact person:Arne Jensen.