Global Renormalization Group

Abstract

The motivation and the challenge in applying the renormalization group for systems with several scaling regimes is briefly outlined. The four dimensional $\phi^4$ model serves as an example where a nontrivial low energy scaling regime is identified in the vicinity of the spinodal instability region. It is pointed out that the effective theory defined in the vicinity of the spinodal instability offers an amplification mechanism, a precursor of the condensation that can be used to explore nonuniversal forces at high energies.