Duality and universal transport in mixed-dimension electrodynamics

Using the recently conjectured fermion particle-vortex duality, the authors demonstrate that the theory of a single (2+1)-dimensional Dirac fermion coupled to an Abelian gauge field in a (3+1)-dimensional bulk exhibits a strong-weak duality. The duality is a manifestation of the electromagnetic S-duality in the bulk. At the self-dual point, they find several exact relations between transport coefficients, such as conductivity, Hall conductivity, and thermoelectric coefficients. Consequently, the duality provides new constraints on the physics of a strongly interacting system.