Many-body superconductivity in topological flat bands
4 affiliations
- 1Department of Physics, Princeton University, Princeton, NJ, USA
- 2Department of Applied Physics, Aalto University School of Science, Aalto, Finland
- 3Donostia International Physics Center, Donostia-San Sebastian, Spain
- 4IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
Abstract
In a flat band superconductor, bosonic excitations disperse while unpaired electrons are immobile. To study this strongly interacting system, we construct a family of multi-band Hubbard models with exact eta-pairing ground states in all space groups. We analytically compute their many-body excitations and find that the Cooper pair bound states obey an effective single-boson hopping Hamiltonian written in terms of the non-interacting wavefunctions. These bound states possess a unique zero-energy excitation whose quadratic dispersion is determined by the minimal quantum metric. The rest of the bound state spectrum is classified by topological quantum chemistry, which we use to identify Cooper pairs with Weyl nodes, higher angular momentum pairing, and fragile topology. Broadening the band dispersion, we find the strongest pairing occurs at half filling and not at the highest density of states. Our analytical results prove that the elementary fermionic and bosonic excitations, corresponding respectively to pairing and coherence, are governed by distinct properties of the flat band, rigorously establishing its unique phenomenology. Superconductivity in flat bands is a central feature of quantum geometric effects, supported by mean-field theory and numerics. Here, the authors exhibit a large family of flat band Hubbard models whose ground states, Bogoliubov-de-Gennes particles, and Cooper pairs are exactly solvable with analytically calculable dispersions.
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BibTeX
@article{herzogarbeitman2026manybody,
title = {{Many-body superconductivity in topological flat bands}},
author = {Jonah Herzog-Arbeitman and Aaron Chew and Kukka-Emilia Huhtinen and Päivi Törmä and Bogdan Andrei Bernevig},
journal = {Communications Physics},
year = {2026},
month = jul,
doi = {10.1038/s42005-026-02732-2},
url = {https://doi.org/10.1038/s42005-026-02732-2},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Many-body superconductivity in topological flat bands
AU - Jonah Herzog-Arbeitman
AU - Aaron Chew
AU - Kukka-Emilia Huhtinen
AU - Päivi Törmä
AU - Bogdan Andrei Bernevig
PY - 2026
DA - 2026/07/04
JO - Communications Physics
DO - 10.1038/s42005-026-02732-2
UR - https://doi.org/10.1038/s42005-026-02732-2
AB - In a flat band superconductor, bosonic excitations disperse while unpaired electrons are immobile. To study this strongly interacting system, we construct a family of multi-band Hubbard models with exact eta-pairing ground states in all space groups. We analytically compute their many-body excitations and find that the Cooper pair bound states obey an effective single-boson hopping Hamiltonian written in terms of the non-interacting wavefunctions. These bound states possess a unique zero-energy excitation whose quadratic dispersion is determined by the minimal quantum metric. The rest of the bound state spectrum is classified by topological quantum chemistry, which we use to identify Cooper pairs with Weyl nodes, higher angular momentum pairing, and fragile topology. Broadening the band dispersion, we find the strongest pairing occurs at half filling and not at the highest density of states. Our analytical results prove that the elementary fermionic and bosonic excitations, corresponding respectively to pairing and coherence, are governed by distinct properties of the flat band, rigorously establishing its unique phenomenology. Superconductivity in flat bands is a central feature of quantum geometric effects, supported by mean-field theory and numerics. Here, the authors exhibit a large family of flat band Hubbard models whose ground states, Bogoliubov-de-Gennes particles, and Cooper pairs are exactly solvable with analytically calculable dispersions.
SN - 2399-3650
ER -