One of the American Institute of Physics’s top stories of the year 2005 was the discovery of the quark gluon plasma at RHIC. In this paper, the basic theory of the quark gluon plasma is reviewed, and the experimental evidence from RHIC discussed.

We compute the hard photon production rate of a chemically non-equilibrated quark-gluon plasma. We assume that the plasma is already thermally equili-brated, i. e. describable by a temperature, but with a phase-space distribution that deviates from the Fermi/Bose distribution by a time dependent factor (fugacity). The photon spectrum is obtained by integrating the photon rate over the space-tim...