Effective confining potentials for QCD
  We observe that the linear potential used as a leading approximation for describing color confinement in the instant form of dynamics corresponds to a quadratic confining potential in the front form of dynamics. In particular, the instant-form potentials obtained from lattice gauge theory and string models of hadrons agree with the potentials determined from models using front-form dynamics and light-front holography, not only in their shape, but also in their numerical strength. 
Arkadiusz P. Trawi\'nski, Stanis{\l}aw D. G{\l}azek, Stanley J.   Brodsky, Guy F. de T\'eramond, Hans G\"unter Dosch
hep-ph