Non-trivial topological structure of heat and momentum flux radiated by magneto-optical nanoparticles

In the present Letter we investigate the heat and momentum fluxes radiated by a hot magneto-optical nanoparticle in its surrounding under the action of an external magnetic field. We show that the flux lines circulate in a confined region at nanometric distance from the particle around the axis of magnetic field in a vortex-like configuration. Moreover we prove that the spatial orientation of these vortices (clockwise or counterclockwise) is associated to the contribution of optical resonances with topological charges m = +1 or m = -1 to the thermal emission. This work paves the way to a geometric description of heat and momentum transport in lattices of magneto-optical particles. Moreover it could have important applications in the field of energy storage as well as in thermal management at nanoscale.