Chiral condensates in the light-cone vacuum - art. no. 045018

In light-cone quantization, the standard procedure to characterize the phas es of a system by appropriate ground state expectation values fails. The li ght-cone vacuum is determined kinematically. We show that meaningful quanti ties which can serve as order parameters are obtained as expectation values of Heisenberg operators in the equal (light-cone) time limit. These quanti ties differ from the purely kinematical expectation values of the correspon ding Schrodinger operators. For the Nambu-Jona-Lasinio and the Gross-Neveu model, we describe the spontaneous breakdown of chiral symmetry; we derive within light-cone quantization the corresponding gap equations and the valu es of the chiral condensate.