Instanton Prefactor: Derivation and Applications

This lecture covers the computation of the instanton pre-factor in the context of a charged particle interacting with an external electromagnetic field. The slides discuss the derivation of the instanton pre-factor, the double well potential, dilute instanton approximation, and nonperturbative energy splitting. The lecture also explores the twisted partition function, perturbative corrections, and the validity of dilute instanton approximation. Additionally, it delves into the avoidance of multi-instantons, twisted partition function representation, and the path integral representation of the twisted partition function. The presentation concludes with a study of the twisted partition function's determinant, exclusion of zero modes, and the Gelfand-Yaglom equation revisited.