Speaker
Description
Instantons play a central role in the semiclassical description of non-perturbative phenomena in gauge theories. Their calculation, however, can be delicate in some subtle settings, notably in theories with spontaneous symmetry breaking and in problems involving finite non-compact spacetime. In this talk, I revisit selected issues in instanton calculations in such settings.
One possible focus is the treatment of instanton contributions in the broken phase, where constraints are needed to construct the relevant semiclassical configurations. Another possible focus is instanton calculations on finite non-compact spacetime, where boundary conditions and controlled limiting procedures must be specified carefully. Depending on the emphasis of the talk, I will discuss one or both of these themes.
The selected topics include the case of spontaneous symmetry breaking, based on arXiv:2604.02987 [hep-th], and the finite non-compact spacetime case, based on ongoing work.