Monopoles, Clarified

ABSTRACT We propose a manifestly duality‐invariant, Lorentz‐invariant, and local action to describe quantum electrodynamics in the presence of magnetic monopoles that derives from Sen's formalism. By employing field strengths as the dynamical variables, rather than potentials, this formalism resolves longstanding ambiguities in prior frameworks. Our analysis finds consistent outcomes at both tree and loop levels using the established principles of quantum field theory, obviating the need for external assumptions or amendments. We clarify the mechanisms of charge renormalization and demonstrate the renormalization group invariance of the charge quantization condition. Our approach can be useful for phenomenological studies and in quantum field theories with strong–weak dualities.