From nodal liquid to nodal charge gap in a frustrated Hubbard model
Bibliographic record
Abstract
We investigate the physics of frustrated three-leg Hubbard ladders in the band limit when hopping across the ladder's rungs ${(t}_{\ensuremath{\perp}})$ is of the same order as hopping along them (t) and much greater than the onsite Coulomb repulsion $(U).$ We show that this model exhibits a striking electron-hole asymmetry close to half filling: the hole-doped system at low temperatures develops a resonating valence bond (RVB)-like d-wave gap [pseudogap close to $(\ensuremath{\pi},0)]$ coinciding with gapless nodal excitations (nodal liquid); in contrast, the electron-doped system is seen to develop a Mott gap at the nodes, whilst retaining a metallic character of its majority Fermi surface. At lower temperatures in the electron-doped case, d-wave superconducting correlations---here, coexisting with gapped nodal excitations---are already seen to arise. Upon further doping the hole-doped case, the RVB-like state yields to d-wave superconductivity. Such physics is reminiscent of that exhibited by the high- temperature cuprate superconductors, notably electron-hole asymmetry as noted by angle-resolved photoemission spectroscopy and the resistivity exponents observed. This toy model also reinforces the importance of a more thorough experimental investigation of the known three-leg ladder cuprate systems, and may have some bearing on low-dimensional organic superconductors.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".