We propose a model for the description of strongly interacting quarks and gluon quasiparticles at T = (1 − 3)Tc, as a classical and nonrelativistic colored Coulomb gas. The sign and strength of the inter-particle interactions are fixed by the scalar product of their classical color vectors subject to Wong's equations. The model displays a number of phases as the Coulomb coupling is increased ranging from a gas, to a liquid, to a crystal with antiferromagnetic-like color ordering. We analyze the model using Molecular Dynamics (MD) simulations and discuss the density-density correlator in real time. We extract pertinent decorrelation times, diffusion and viscosity constants for all phases. The classical results when extrapolated to the sQGP suggest that the phase is liquid-like, with a diffusion constant D ≈ 0.1/T and a bulk viscosity to entropy density ratio η/s ≈ 1/3. * We do not use kB and thus measure temperature in energy units. † Note that the standard notations used in EM and QCD differ by 4π in the Lagrangian and all subsequent formulae.

Feshbach resonances of trapped ultracold alkali atoms allow to vary the atomic scattering length a. At very large values of a the system enters an universal strongly coupled regime in which its properties-the ground state energy, pressure etc.-become independent of a. We discuss transport properties of such systems. In particular, the universality arguments imply that the shear viscosity of ultracold Fermi atoms at the Feschbach resonance is proportional to the particle number density n, and the Plank constanth: η =hnαη, where αη is a universal constant. Using Heisenberg uncertainty principle and Einstein's relation between diffusion and viscosity we argue that the viscosity has the lower bound given by αη ≤ (6π) −1 . We relate the damping of low-frequency density oscillations of ultracold optically trapped 6 Li atoms to viscosity and find that the value of the coefficient αη is about 0.3. We also show that such a small viscosity can not be explained by kinetic theory based on binary scattering. We conclude that the system of ultracold atoms near the Feshbach resonance is a near-ideal liquid.

The nature of the nonrelativistic nucleon-nucleon potential in the large-N c limit is discussed. In particular, we address the consistency of the meson-exchange picture of nucleon interactions. It is shown that the nonrelativistic nucleon-nucleon potential extracted from the Feynmann graphs up to and including two-mesonexchange diagrams satisfies the spin-flavor counting rules of Kaplan and Savage and of Kaplan and Manohar, provided the nucleon momenta is of order N c 0 . The key to this is a cancellation of the retardation effect of the box graphs against the contributions of the crossed-box diagram. The consistency requires including ⌬ as an intermediate state.