Geometry, Gauge Redundancy, and Quantum Effective Actions
par
Salle 1180, bâtiment E2
Salle des séminaires
This talk will begin with the basic geometric formulation of gauge theories, introducing field space, gauge orbits, and orbit-adapted coordinates that distinguish physical degrees of freedom from gauge directions.
Building on this framework, we will examine the Vilkovisky–DeWitt construction of the gauge-invariant effective action, with particular emphasis on the connection between gauge-fixing independence and reparametrisation invariance in field space. The discussion will then turn to applications in Yang–Mills theory and quantum gravity. Finally, the talk will explore aspects of the Zassenhaus formula and its potential as an alternative computational approach to methods based on heat-kernel coefficients.
The talk is intended as an accessible introduction to the geometry underlying gauge-independent effective actions, complemented by selected applications and computational techniques.