Separating the scales of confinement and chiral-symmetry breaking in lattice QCD with fundamental quarks

Suggested holographic duals of QCD, based on AdS/CFT duality, predict that one should be able to vary the scales of color confinement and chiral-symmetry breaking independently. Furthermore they suggest that such independent variation of scales can be achieved by the inclusion of extra 4-fermion interactions in QCD. We simulate lattice QCD with such extra 4-fermion terms at finite temperatures and show that for strong enough 4-fermion couplings the deconfinement transition occurs at a lower temperature than the chiral-symmetry restoration transition. Moreover the separation of these transitions depends on the size of the 4-fermion coupling, confirming the predictions from the proposed holographic dual of QCD. We use simpler 4-fermion interactions than those suggested by these dual theories to facilitate our simulations. This is because we believe that the physics we wish to study should be insensitive to the precise form of these interactions.