Quasi-particle functional renormalisation group calculations in the two-dimensional t-t'-Hubbard model
Daniel Rohe
SciPost Phys. 15, 192 (2023) · published 13 November 2023
- doi: 10.21468/SciPostPhys.15.5.192
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Abstract
We extend and apply a recently introduced quasi-particle functional renormalisation group scheme to the two-dimensional Hubbard model with next-nearest-neighbour hopping and away from half filling. We confirm the generation of superconducting correlations in some regions of the phase diagram, but also find that the inclusion of self-energy feedback by means of a decreasing quasi-particle weight can suppress superconducting tendencies more than anti-ferromagnetic correlations by which they are generated. As a supplement, we provide sample results for the self-energy in second-order perturbation theory and address some conceptual matters.