April 10th -Thursday- 12:10

"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