We propose a novel parametrization of the four-point vertex function in the one-loop one-particle irreducible renormalization group (RG) scheme for fermions. It is based on a decomposition of the effective two-fermion interaction into fermion bilinears that interact via exchange bosons. Besides being more efficient than previous N-patch schemes, this parametrization also reduces the ambiguity of introducing boson fields. We apply this parametrization to the two-dimensional (t,t')-Hubbard model using a novel Ω-frequency regularization.
@article{arxiv.0902.1651,
title = {Efficient Fermionic One-Loop RG for the 2D Hubbard Model at Van Hove Filling},
author = {Christoph Husemann and Manfred Salmhofer},
journal= {arXiv preprint arXiv:0902.1651},
year = {2009}
}