MINIMAL RENORMALIZATION WITHOUT EPSILON-EXPANSION - CRITICAL-BEHAVIOR ABOVE AND BELOW TC

We present a field-theoretic renormalization-group treatment of the critical behavior of the cphi4 model within the minimal-subtraction scheme at fixed dimension d<4. We show that correlation functions above and below Tc can be calculated within this renormalization scheme without using the =4-d expansion. This is demonstrated for the specific heat, for the order parameter, and for the superfluid density (stiffness constant). Various asymptotic amplitudes and correction amplitudes are determined, and some of their universal ratios are calculated in three dimensions. Our result for ac-/as eliminates a previous error of the expansion regarding the sign of this ratio for d=3 and n=2. © 1990 The American Physical Society.