1. The problem statement, all variables and given/known data I'm trying to derive the stefan-boltzman law by considering a box of photons (as in Landau and Lifgarbagez and other texts). At one point in the derivation we multiply the density of states by 2 in order to account for the two independent polarizations of a photon. But at what point do we account for the fact that the spin of the photon is 1, so we have the "three" independent spin states, -1, 0, and 1? Or is there a relationship between "spin" and "polarization" that no one told me about? 2. Relevant equations The number of states with frequency between w and w+dw is [tex]2 V d^3w \over (2\pi)^3[/tex] V is the volume of the box, the rest of the stuff is from the phase space volume element and the factor 2 out front accounts for the two polarizations. 3. The attempt at a solution I read an older post about helicity of a photon. The poster mentioned something about a photon not being found in a spin 0 state. I didn't fully understand what he/she was saying. But it made me think that maybe 'polarity' and 'spin' are the same thing for a photon, and that the two polarities just correspond to two of the allowed spins while the third possible spin is just forbidden for some reason.