Yeah, as Shankar says, this is only for conduction (and maybe convection?). The assumption about transition probabilities is abstractly saying there’s a lot of contact between the subsystems. If two objects contact each other in a small surface area, this post doesn’t apply and you’ll need to model the heat flow with the heat equation. I suppose radiative cooling acts abstractly like a narrow contact region, only allowing photons through.
Yeah, as Shankar says, this is only for conduction (and maybe convection?). The assumption about transition probabilities is abstractly saying there’s a lot of contact between the subsystems. If two objects contact each other in a small surface area, this post doesn’t apply and you’ll need to model the heat flow with the heat equation. I suppose radiative cooling acts abstractly like a narrow contact region, only allowing photons through.