Soliton mass and surface tension in the (λ|Ø|4)2 quantum field model

Abstract

The spectrum of the mass operator on the soliton sectors of the anisotropic (λ|o|4)2—and the (λo4)2—quantum field models in the two phase region is analyzed. It is proven that, for small enough λ>0, the mass gapm s(λ) on the soliton sector is positive, andm s(λ)=0(λ−1). This involves estimatingm s(λ) from below by a quantity τ(λ) analogous to the surface tension in the statistical mechanics of two dimensional, classical spin systems and then estimating τ(λ) by methods of Euclidean field theory. In principle, our methods apply to any two dimensional quantum field model with a spontaneously broken, internal symmetry group.