Massless fermions and anyons on the surface of (3+1)-dimensional topological insulators can be described at the semiclassical level by a non-local Abelian gauge theory involving two gauge fields. The theory is non-trivial owing to its solitonic excitations with electric and magnetic charges. We compute the partition function and the solitonic spectrum, thus showing conformal invariance and electric-magnetic self-duality. This theory also provides a framework for semiclassical bosonization of (2+1)d fermions. [The talk will also be streamed online, please ask the organizers for the link.]

INFN and Department of Physics, Florence, Italy