Perturbative methods in Algebraic QFT with applications to Thermal Field Theory

par Nicolo Drago (Università degli Studi di Genova)

vendredi 7 avr. 2017, 14:00 → 15:00 Europe/Paris

112 (Institut Camille Jordan)

The Principle of Perturbative Agreement (PPA), as introduced by Hollands & Wald, is a renormalisation condition in quantum field theory on curved spacetimes. This principle states that the perturbative and exact constructions of a field theoretic model given by the sum of a free and an exactly tractable interaction Lagrangian should agree. We develop a proof of the validity of the PPA in the case of scalar fields and quadratic interactions without derivatives which differs in strategy from the one given by Hollands & Wald for the case of quadratic interactions encoding a change of metric. Afterwards, we prove a generalization of the PPA and show that considering an arbitrary quadratic contribution of a general interaction either as part of the free theory or as part of the perturbation gives equivalent results. Finally, we will briefly describe how our findings can be used in order to provide a mathematically rigorous description of the "thermal mass" idea used in Physics.