Renormalisation group recursions by mean-field approximations

Abstract

Within a renormalisation group strategy, different 'rescaled' mean-field approximations for the magnetisation are combined. Good qualitative estimates are obtained for the critical properties of classical and quantum spin systems. A particularly simple realisation of the method yields recursions for arbitrary dimensionality d. The critical couplings are accurate for all d, and have the correct asymptotic behaviour for d approaching infinity