The Global Renormalization Group Trajectory in a Critical Supersymmetric Field Theory on the Lattice Z^3

Abstract

We consider an Euclidean supersymmetric field theory in $Z^3$ given by a supersymmetric ${\Phi }^4$ perturbation of an underlying massless Gaussian measure on scalar bosonic and Grassmann fields with covariance the Green's function of a (stable) Lévy random walk in $Z^3$. The Green's function depends on the Lévy-Khintchine parameter $\alpha =\frac{3+\epsilon }{2}$ with $0<\alpha <2$. For $\alpha =\frac{3}{2}$ the ${\Phi }^4$ interaction is marginal. We prove for $\alpha -\frac{3}{2}=\frac{\epsilon }{2}>0$ sufficiently small and initial parameters held in an appropriate domain the existence of a global renormalization group trajectory uniformly bounded on all renormalization group scales and therefore on lattices which become arbitrarily fine. At the same time we establish the existence of the critical (stable) manifold. The interactions are uniformly bounded away from zero on all scales and therefore we are constructing a non-Gaussian supersymmetric field theory on all scales. The interest of this theory comes from the easily established fact that the Green's function of a (weakly) self-avoiding Lévy walk in $Z^3$ is a second moment (two point correlation function) of the supersymmetric measure governing this model. The control of the renormalization group trajectory is a preparation for the study of the asymptotics of this Green's function. The rigorous control of the critical renormalization group trajectory is a preparation for the study of the critical exponents of the (weakly) self-avoiding Lévy walk in $Z^3$.

82 pages, Tex with macros supplied. Revision includes 1. redefinition of norms involving fermions to ensure uniqueness. 2. change in the definition of lattice blocks and lattice polymer activities. 3. Some proofs have been reworked. 4. New lemmas 5.4A, 5.14A, and new Theorem 6.6. 5.Typos corrected.This is the version to appear in Journal of Statistical Physics

References in corpus (2)

• A Complete Renormalization Group Trajectory Between Two Fixed Points
• End-to-end Distance from the Green's Function for a Hierarchical Self-Avoiding Walk in Four Dimensions

Cited by in corpus (1)

• Functional integral representations for self-avoiding walk