Strong Coupling Universality at Large N for Pure CFT Thermodynamics in 2+1 dimensions

Understand

Pure CFTs have vanishing $\beta$-function at any value of the coupling.

• One example of a pure CFT is the O(N) Wess-Zumino model in 2+1 dimensions in the large N limit.
• This model can be analytically solved at finite temperature for any value of the coupling, and we find that its entropy density at strong coupling is exactly equal to 31/35 of the non-interacting Stefan-Boltzmann result.
• We show that a large class of theories with equal numbers of N-component fermions and bosons, supersymmetric or not, for a large class of interactions, exhibit the same universal ratio.