Perfect heat rectification and circulation with nonreciprocal radiative surfaces in the far field

Controlling photon-mediated energy flow is central to the future of communications, thermal management, and energy harvesting technologies. Recent breakthroughs have revealed that many-body systems violating Lorentz reciprocity can sustain persistent photon heat current at thermal equilibrium, hinting at a paradigm of heat flow akin to superconductivity. Yet, the behavior of such systems far from equilibrium remains largely unexplored. In this work, we uncover the rich physics of radiative heat transfer in nonequilibrium, far-field many-body systems composed of thermal emitters that break Lorentz reciprocity. We show that the total heat flow naturally decomposes into two distinct components: an equilibrium term, which generates a persistent circulating heat current within the system, and a nonequilibrium term, which governs energy exchange with the environment. Remarkably, while the internal persistent heat current is ever-present, the nonequilibrium contribution can be precisely engineered to achieve perfect heat rectification and circulation. Our results open a route toward designing thermal systems with unprecedented control—unlocking the potential for lossless heat circulation and one-way thermal devices. This fundamentally shifts the landscape for next-generation thermal logic, energy conversion, and photonic heat engines.