Numerical study of the local contractivity of the $\Phi_0^4$ mapping

Abstract

Previous results on the non trivial solution of the $\Phi^4$-equations of motion for the Green's functions in the Euclidean\ space (of $0\leq r\leq 4$ dimensions) in the Wightman Quantum Field theory framework, are reviewed in the $0-$ dimensional case from the following two aspects: (cf.\cite{MM})\ The structure of the subset $\Phi \subset {\cal B}$ characterized by the bounds signs and "splitting" (factorization properties) is reffined and more explictly described in terms of a new closed subset $\Phi_0 \subset \Phi \subset {\cal B}$. Using a new norm we establish the local contractivity of the corresponding $\Phi ^4_0$ mapping in the neighborhood of a nontrivial sequence $H_0\in \Phi_0$. A new $\Phi ^4_0$ iteration is defined in the neighborhood of the sequence $H_0\in \Phi_0 $. In this paper we present the results of our numerical study, so: {a)} \emph{the stability of $\Phi_0$} i.e. the splitting, bounds and sign properties is clearly illustrated in the neighborhood of $H_0\in \Phi_0$. {b)} the \emph{rapid convergence of this iteration} to the fixed point is perfectly realized thanks to the new starting points of the iteration.