Quark Confinement due to Random Interactions
  On the level of an effective quark theory, we define confinement by the absence of quark anti-quark thresholds in correlation functions. We then propose a confining Nambu-Jona-Lasinio-type model. Its four fermion interaction in the color channel is mediated by a random color matrix. We investigate the model's phase structure as well as its behavior under extreme conditions, i.e. high temperature and/or high density. In order to study the interplay of the proposed mechanism of confinement and asymptotic freedom, we consider an extended Gross-Neveu model. Quark anti-quark thresholds are proven to be absent in the scalar correlation function implying that the decay of the scalar meson into free quarks is avoided. The transition from the low energy to the high energy perturbative regime is found to be smooth. Perturbation theory provides a good description of Green's functions at high energies, although there is no quark liberation. 
Kurt Langfeld