Orev Malatesta, PhD candidate with Cattaneo Group, University of Zürich
Every gauge symmetry hides a ghost. What begins in quantum field theory as a computational fix – the Faddeev-Popov trick, which introduces extra “unphysical” fields called ghost fields to keep our path integrals well-behaved – evolves in BRST symmetry into a systematic algebraic framework where gauge symmetries and ghost fields are described on equal footing. Yet BRST has its limits, and the Batalin–Vilkovisky (BV) formalism extends it to theories with more complex gauge structures, where new kinds of ghosts appear. In this talk, we will follow the ghosts through their many guises in QED and QCD, and also pry into gravity, where only BV can handle them.
Recording
The talk will be streamed and there will be a recording.