Analysis of one particle excitations in phenomenological models of QCD
  In these notes for the quark Nambu-Jona-Lasinio model and for the phenomenological four fermionic model of QCD we analyze vacuum energy structure and calculate dependence of energy of one-particle excitations on momentum. We reveal existence of two different types of excitations above the vacuum with the respective minimization of the vacuum energy density. First type of excitation energy spectrum is the usual spectrum of relativistic massive particle, but the second one has a linear dependence on momentum. 
A.N.Vall, S.I.Korenblit, V.M.Leviant, A.V.Sinitskaya