  Using the temperature Green's function approach we investigate entanglement
between two non-interacting spin 1 bosons in thermal equilibrium. We show that,
contrary to the fermion case, the entanglement is absent in the spin density
matrix. Separability is demonstrated using the Peres-Horodecki criterion for
massless particles such as photons in black body radiation. For massive
particles, we show that the density matrix can be decomposed with separable
states.
