Nonperturbative approach to Yang-Mills thermodynamics

An analytical and nonperturbative approach to SU(2) and SU(3) Yang-Mills thermodynamics is developed and applied. Each theory comes in three phases: A deconfining, a preconfining, and a confining one. We show how macroscopic and inert scalar fields form in each phase and how they determine the ground-state physics and the properties of the excitations. While the excitations in the deconfining and preconfining phase are massless or massive gauge modes of spin 1 they are massless or massive spin-1/2 fermions in the confining phase. The nature of the two phase transitions is investigated for each theory. We compute the temperature evolution of thermodynamical quantities in the deconfining and preconfining phase and estimate the density of states in the confining phase. Some implications for particle physics and cosmology are discussed.