Flow of the quasiparticle weight in the N-patch renormalization group   scheme
  Using the N-patch renormalization group method we investigate the flow of the quasiparticle weight in one-dimensional, weakly two-dimensional and fully two-dimensional Hubbard models. In one dimension we reproduce the Luttinger exponent that describes the disappearance of the quasiparticle peak towards lower scales. Further we analyze effects of the band structure, interchain hopping and the flow of the interactions in quasi-one-dimensional models. For the two-dimensional case we study how the suppression of the quasiparticle weight affects the flow to strong coupling. We find that the flow to strong coupling remains essentially unchanged. This strengthens the evidence for d-wave superconductivity in the weakly repulsive Hubbard model. 
Carsten Honerkamp, Manfred Salmhofer