The treatment of gauge theories in the continuum typically requires the introduction of a gauge-fixing condition. In perturbation theory, the ingenious Faddeev-Popov trick is widely used allowing for the explicit evaluation of gauge fields propagators. However, in stronglycoupled regimes, the assumptions behind the Faddeev-Popov construction do not hold. Gauge fields that fulfil the gauge condition and are connected by gauge transformations are still present in the configuration space – they are the so-called Gribov copies. In this talk, I will present an overview of the problem together with recent developments on how to deal with gauge copies in practice. Most of the presentation will be focused on Yang-Mills theories, but comments that are relevant for the quantum-field theoretic formulation of quantum gravity will be made whenever possible.
This video was produced by the University of Münster, as part of the workshop From perturbative to non-perturbative QFT.
