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Main Authors: Fontana, Pierpaolo, Lepori, Luca, Trombettoni, Andrea
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2604.19332
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author Fontana, Pierpaolo
Lepori, Luca
Trombettoni, Andrea
author_facet Fontana, Pierpaolo
Lepori, Luca
Trombettoni, Andrea
contents The three-dimensional Hofstadter model exhibits a critical rational flux at which Weyl points emerge in the single-particle spectrum. We study the superconducting regime of the model in the presence of a Hubbard attractive interaction by tuning the magnetic flux across its critical value. We determine the phase diagram in the plane of the coprime pairs parametrizing the magnetic flux. We show that the system exhibits two distinct regimes separated by a critical flux $Φ_c$: for $Φ>Φ_c$, a semimetal-to-superconductor quantum phase transition occurs at a finite interaction strength ($U_c\neq0$), while for $Φ<Φ_c$ superconductivity arises for arbitrarily weak attraction, with a BCS-like exponential scaling of the gap due to the finiteness of the density of states. Close to the transition, we study the scaling behavior and identify the critical exponents. Our results highlight the interplay between magnetic band topology and attractive pairing in three-dimensional Hofstadter systems.
format Preprint
id arxiv_https___arxiv_org_abs_2604_19332
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Superconducting properties of the three-dimensional Hofstadter-Hubbard model below the critical flux for Weyl points
Fontana, Pierpaolo
Lepori, Luca
Trombettoni, Andrea
Strongly Correlated Electrons
Superconductivity
The three-dimensional Hofstadter model exhibits a critical rational flux at which Weyl points emerge in the single-particle spectrum. We study the superconducting regime of the model in the presence of a Hubbard attractive interaction by tuning the magnetic flux across its critical value. We determine the phase diagram in the plane of the coprime pairs parametrizing the magnetic flux. We show that the system exhibits two distinct regimes separated by a critical flux $Φ_c$: for $Φ>Φ_c$, a semimetal-to-superconductor quantum phase transition occurs at a finite interaction strength ($U_c\neq0$), while for $Φ<Φ_c$ superconductivity arises for arbitrarily weak attraction, with a BCS-like exponential scaling of the gap due to the finiteness of the density of states. Close to the transition, we study the scaling behavior and identify the critical exponents. Our results highlight the interplay between magnetic band topology and attractive pairing in three-dimensional Hofstadter systems.
title Superconducting properties of the three-dimensional Hofstadter-Hubbard model below the critical flux for Weyl points
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2604.19332