arXiv2026
In this paper, I calculated the partition function of the quantum statistical system of free massless higher spin (HS) bosonic fields with zero chemical potential value on $d$-dimensional Minkowski spacetime by using Feynman's path integral approach, which is a nontrivial result that explains the self-duality between the quantum statistical system of these fields of $s \geq 2$ over $d \geq 4$ dimensional Minkowski spacetime and the quantum statistical system of Klein-Gordon bosonic fields on 4-dimensional Minkowski spacetime at thermal equilibrium. However, I used the dimensional regularization approach to determine the free energy of this system, and the results indicate that the presence of ultraviolet divergences (UV) could possibly be eliminated, which also ensures that Lorentz and gauge symmetries are preserved at thermal equilibrium. In particular, the most significant result is that the average energy spectrum of the quantum statistical system of massless free bosonic HS fields is similar to the blackbody radiation energy spectrum at different temperatures. It also explains the universe's cosmic microwave background (CMB) radiation spectrum (COBE data) at a 2.7 Kelvin temperature. The average energy spectrum of this system decreases with increasing $β$ value, as shown in this paper. However, the entropy of these fields also explains their self-duality with Klein-Gordon bosonic fields in 4-dimensional Minkowski spacetime. In this paper, I discussed the spontaneous symmetry breaking in the interacting bosonic higher spin fields on $d$-dimensional Minkowski spacetime, as well as the breakdown of self-duality between the interacting quantum statistical system of bosonic higher spin fields over $d\geq 4$-dimensional Minkowski spacetime and Klein-Gordon bosonic fields at thermal equilibrium points over 4-dimensional Minkowski spacetime.