  In this Letter a N-body theory for the radiative heat exchange in thermally
non equilibrated discrete systems of finite size objects is presented. We
report strong exaltation effects of heat flux which can be explained only by
taking into account the presence of many body interactions. Our theory extends
the standard Polder and van Hove stochastic formalism used to evaluate heat
exchanges between two objects isolated from their environment to a collection
of objects in mutual interaction. It gives a natural theoretical framework to
investigate the photon heat transport properties of complex systems at
mesoscopic scale.
