Duality relation between radiation thermodynamics and cosmic string loop thermodynamics

We discuss thermodynamics of electromagnetic radiation and of cosmic string loops. We write the thermodynamic formalisms under a common framework that illustrates their formal relationship and allows us to go from one to the other through a smoothtransformation. From a microscopic perspective, these relations arise from a energy relations for the photons of electromagnetic radiation, and for cosmic string loops. The corresponding thermodynamic behaviors are seen to be connected through a related thermal duality.