Global Currents, Phase Transitions, and Chiral Symmetry Breaking in Large N_c Gauge Theory

We study, using a gravity dual, the finite temperature dynamics of $SU(N_c)$ gauge theory for large $N_c$, with fundamental quark flavours in a quenched approximation, in the presence of a fixed R--charge under a global R--current. We observe several notable phenomena. There is a first order phase transition where the quark condensate jumps discontinuously at finite quark mass, generalizing similar transitions seen at zero charge. Our tool in these studies is holography, the string dual of the gauge theory being the geometry of $N_c$ spinning D3--branes at finite temperature, probed by a D7--brane.