Perturbative renormalization of the lattice regularized $\phi_4^4$ with flow equations

Abstract

The flow equations of the renormalization group allow to analyse the perturbative $n$-point functions of renormalizable quantum filed theories. Rigorous bounds implying renormalizability permit to control large momentum behaviour, infrared singularities and large order behaviour in the number of loops and the number of arguments $n$. In this paper, we analyse the Euclidean $4$-dimensional massive $\phi_4$-theory using lattice regularization. We present a rigorous proof that this quantum field theory is renormalizable, to all orders of the loop expansion based on the flow equations. The lattice is known to break the Euclidean symmetry of the space-time. Our main result is the proof of the restoration of the Euclidean symmetries using the flow equations.