title: Manifestation of a nontrivial vacuum in discrete light-cone quantization.
abstract: We study a (1+1)-dimensional lambda phi(4) model with a light-cone zero mode and constant external source to describe spontaneous symmetry breaking. In the broken phase, we find degenerate vacua and discuss their stability based on effective-potential analysis. The vacuum triviality is spurious in the broken phase because these states have lower energy than Fock vacuum. Our results are based on the variational principle.
authors.affiliation: Department of Physics, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sugihara
authors.forename: M
authors.initials: M
authors.lastname: Taniguchi