Alexander Monin: Multiparticle processes, large charge and semiclassics

Thursday 8 Oct 2020, 15:00 → 16:00 Europe/Zurich

Zoom only (CERN)

Understanding the behavior of a cross section at high enough energies, when the number of particles in the final state is large, is an important and yet unsolved subject. The difficulty in addressing the question is inapplicability of the standard perturbation theory for describing processes with many quanta even in weakly coupled theories. However, a certain reorganization (similar to RG improvement) of the perturbative expansion indicates a possibility of a semiclassical description: in other words perturbation theory around a non-trivial saddle. First, I’ll present the current state of affairs with regards to a scalar $\lambda \phi^4$ theory. And later I’ll show an explicit and consistent construction allowing to compute observables like anomalous dimension etc. for operators with arbitrary large charge in $U(1)$ symmetric scalar field theory at Wilson-Fisher fixed point.

https://cern.zoom.us/j/99113688676