The Ising model and bubbles in the quark-gluon plasma

I review evidence for the stability of bubbles in the quark-gluon plasma near the confinement phase transition. In analogy with the much-studied oil-water emulsions, this raises the possibility that there are many phases between the pure plasma and the pure hadron gas, characterized by spontaneous inhomogeneity and modulation. In studying emulsions, statistical physicists have reproduced many of their phases with microscopic models based on Ising-like theories with competing interactions. Hence we seek an effective Ising Hamiltonian for the SU(3) gauge theory near its transition.