Functional Renormalization Group calculation of the Fermi surface of a spin-ladder

TL;DR

This paper uses functional Renormalization Group methods to precisely calculate the Fermi surface of a spin-ladder, enhancing understanding of non-conventional superconductivity in low-dimensional systems.

Contribution

It provides an exact solution for the Fermi surface of a single ladder using FRG, improving predictions of the Hubbard model for low-dimensional superconductors.

Findings

Superconducting phase shows stabilized binding/antibinding gap.

Antiferromagnetic phase gap shrinks, indicating a transition to one-dimensional behavior.

FRG scheme dependence noted in results.

Abstract

We study non conventional superconductivity on a ladder, improving the predictions of the Hubbard model. The determination of the Fermi surface, in 2 or 3 dimensions, remains a very hard task, but it is exactly solvable for a single ladder. We use functional Renormalisation Group methods, which prove, here, scheme-dependant. In the superconducting phase, the binding/antibinding gap is stabilized, but in the antiferromagnetic phase, it shrinks and the ladder turns one-dimensional.