Jian-Sheng Wang National University of Singapore

##### Energy, momentum, and angular momentum transfers mediated by photons

Consider N objects in vacuum each locally may in thermal equilibrium but globally in nonequilibrium steady state. Transport of energy, momentum, or angular momentum is then possible mediated by the electromagnetic fields. It is useful to consider also an extra N+1 “object” which is the “bath-at-infinity”. Very general formulas of Meir-Wingreen type are derived based on the nonequilibrium Green’s functions for the photon field and the Keldysh formalism. The materials properties are represented by self energies. We illustrate the usefulness of the formulas and present some results of calculations, such as the angular momentum emission by a benzene ring driven by electric current, energy and angular momentum emission from a Haldane model of electrons, and also from graphene edges in nonequilibrium states.

Video of the lecture