Damiano Anselmi (Pisa U.), The diagrammatics of physical and purely virtual particles in quantum field theory

Tuesday 2 May 2023, 14:00 → 15:30 Europe/Stockholm

Albano 3: 6228 - Mega (22 seats) (Albano Building 3)

Quantum field theory is to a large extent expressed in the language of diagrams. I compare known types of diagrams (Feynman, Cutkosky-Veltman, Keldysh) to diagrams of new types, which allow us to define new ``particles'' (purely virtual particles) and new theories, including a way out for the quantization of gravity. I also show how the diagrammatics works when quantum field theory is restricted to a finite interval of time and a compact space manifold. Finally, I discuss the dressed propagators in various key cases, some new effects and their impact on cosmology.