"The adiabatic limit in causal perturbation theory"

Pawel Duch

(Universidad Jagielloniana, Cracovia,
Polonia)

The talk will be devoted to the causal perturbation theory -- a
mathematically rigorous approach to perturbative quantum field theory
developed by Epstein and Glaser, which does not require the
introduction of any ultraviolet regularization.
One of the characteristic features of this approach is the use of a
"switching function" in the intermediate steps of the construction of
the scattering matrix and the interacting fields. The switching
function plays the role of infrared regulator, which is removed by
taking the adiabatic limit.
After an overview of different types of the adiabatic limit in
perturbative quantum field theory, the recent proof of the existence
of the so-called weak adiabatic limit will be discussed. The result
allows to construct the Wightman and Green functions for a large class
of theories, including all models with interaction vertices of
dimension four.

Facultad de Ciencias

Seminario de Física Teórica
Universidad de Zaragoza