Bibliographic record
Abstract
We explore the possible particle-hole instabilities that can arise in a system of massless Dirac fermions on both the honeycomb and $\ensuremath{\pi}$-flux square lattices with short range interactions. Through analytical and numerical studies we show that these instabilities can result in a number of interesting phases. In addition to the previously identified charge and spin density wave phases and the exotic ``quantum anomalous Hall'' (Haldane) phase, we establish the existence of the dimerized ``Kekul\'e'' phase over a significant portion of the phase diagram and discuss the possibility of its spinful counterpart, the ``spin Kekul\'e'' phase. On the $\ensuremath{\pi}$-flux square lattice we also find various stripe phases, which do not occur on the honeycomb lattice. The Kekul\'e phase is described by a ${\text{Z}}_{3}$ order parameter whose singly quantized vortices carry fractional charge $\ifmmode\pm\else\textpm\fi{}e/2$. On the $\ensuremath{\pi}$-flux lattice the analogous dimerized phase is described by a ${\text{Z}}_{4}$ order parameter. We perform a fully self-consistent calculation of the vortex structure inside the dimerized phase and find that close to the core the vortex resembles a familiar superconducting U(1) vortex, but at longer length scales a clear ${Z}_{4}$ structure emerges with domain walls along the lattice diagonals.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".