The quark-gluon plasma and D6-branes on the conifold

We investigate the possibility of constructing a supergravity background dual to the quark-gluon plasma using D6-branes wrapping a three-cycle in the deformed conifold. The UV-completion of this setup is given by M-theory on a G2 holonomy manifold. For the class of metrics considered we find that there are only non-extremal D-brane solutions in the limit of the singular conifold with the singularity being resolved by the D-brane horizon. The thermodynamic properties of the system show some puzzling features, such as negative specific heat at an unusual behavior of the entropy. Among the properties of the plasma studied using this holographic dual are the quark-antiquark potential, the shear viscosity and parton energy loss. While one finds the expected behavior for the potential and the viscosity - deconfinement and the universal shear-viscosity to entropy ratio - both the jet quenching parameter and the calculation of the drag force lead us to the conclusion that there is no parton energy loss in the dual plasma. Our results indicate that the background constructed is not dual to a realistic QGP, yet we argue that this should improve upon inclusion of the three-form gauge potential in the eleven-dimensional background.