Hard-soft renormalization and the exact renormalization group

Hard - Soft Renormalization and the Exact Renormalization Group ∗

In gauge theories, after integrating over the hard modes, the Wilsonian functional depending on the soft fields satisfies effective Ward identities. We observe that, enlarging the Wilsonian functional in order to include hard fields, the effective Ward identities arise from a non-local symmetry between the hard and soft fields. Using the flow equation technique, we outline a proof in perturbati...

The Exact Renormalization Group

This is a very brief introduction to Wilson’s Renormalization Group with emphasis on mathematical developments.

Exact Renormalization Group with Fermions

The set of ideas enclosed in the Renormalization Group (RG, hereafter) has led to a variety of developments in many fields, as this Conference has made apparent. From a particle theorist point of view they englobe a bunch of ideas form which we may understand what a quantum field theory is. Moreover, it provides a framework for nonperturbative calculations. In recent years, there has been an in...

The Exact Renormalization Group and Approximate Solutions

We investigate the structure of Polchinski’s formulation of the flow equations for the continuum Wilson effective action. Reinterpretations in terms of I.R. cutoff greens functions are given. A promising non-perturbative approximation scheme is derived by carefully taking the sharp cutoff limit and expanding in ‘irrelevancy’ of operators. We illustrate with two simple models of four dimensional...

Renormalization Group Renormalization Group