Absorption of Heat into a Superconductor-Normal Metal-Superconductor Junction from a Fluctuating Environment

We study a diffusive superconductor-normal-metal-superconductor junction in an environment with intrinsic incoherent fluctuations which couple to the junction through an electromagnetic field. When the temperature of the junction differs from that of the environment, this coupling leads to an energy transfer between the two systems, taking the junction out of equilibrium. We describe this effect in the linear response regime and show that the change in the supercurrent induced by this coupling leads to qualitative changes in the current-phase relation and, for a certain range of parameters, an increase in the critical current of the junction. In addition to normal metals, similar effects can be expected also in other conducting weak links.