Confinement and Chiral Symmetry, a Lattice QCD test of AdS/QCD

We use lattice QCD simulations to test some of the predictions of proposed AdS/QCD (holographic) duals for QCD. In particular, these duals predict that the scale of chiral symmetry breaking ($\chi$SB) can be varied independently from that of confinement, with the proviso that the scale of $\chi$SB cannot be longer than that of confinement. We simulate lattice QCD with 2 quarks in the fundamental representation of colour and with additional 4-fermion interactions (suggested by AdS/QCD), at finite temperatures. For sufficiently strong 4-fermion interactions, the deconfinement and $\chi$SB transitions occur at different temperatures, the separation depending on the 4-fermion coupling. This confirms that the scales of confinement and $\chi$SB are, in general, different.