IsingSquare — model index
The 2D classical Ising model on the square lattice — Onsager's exactly-solved ferromagnet with a finite-temperature order-disorder transition.
\[H = -J\sum_{\langle i,j\rangle} \sigma_i \sigma_j, \qquad \sigma_i = \pm 1\]
Generated by docs/atlas/generate.jl — a pure VIEW over the *_registry.jl claims + the static test/INVENTORY.jsonl AST scan. No test is executed and no src is run; test/INVENTORY.jsonl is regenerated in-place (idempotently) from that static scan; fetch/@register untouched. Assurance labels are PROVISIONAL: residuals / confidence are not shown yet (RES not wired). Badges reflect the committed test AST, not the latest CI run — a hub can read green while its @test is red between regenerations. @sweep = a graceful regime-resolution gap, not card omission.
All (Quantity, BC) hubs src claims for IsingSquare. Cells link to the per-hub card; — = not yet implemented at that BC. The shape of the matrix is the gap visualisation: empty cells are where physics could be added next.
Convention
| Field | Value |
|---|---|
| Hamiltonian | see file-header description above |
| Observable | per src/core/quantities.jl (matches the dispatch tag) |
| Reference | docs/src/conventions.md (project-wide convention policy) |
| STATUS | backfilled by PR (audit gate); per-field domain content |
Coverage
| Level | Count |
|---|---|
| 🟣 universality-corroborated | 0 |
| 🟢 corroborated-at-p | 7 |
| 🔵 coherent | 2 |
| ⚪ cited-only | 0 |
| 🟠 uncorroborated-but-feasible | 4 |
| total claimed hubs | 13 |
Methods (from @register, derived): analytic, central_diff, delegation, onsager, transfer_matrix
Quantity × BC matrix
| Quantity | PBC | Infinite |
|---|---|---|
CriticalExponents | — | 🟠 hub |
CriticalTemperature | — | 🟢 hub |
Energy | 🟢 hub | 🔵 hub |
FreeEnergy | 🟢 hub | 🟠 hub |
PartitionFunction | 🟢 hub | — |
SpecificHeat | 🟢 hub | 🟠 hub |
SpontaneousMagnetization | — | 🟢 hub |
ThermalEntropy | 🟢 hub | 🔵 hub |
UniversalityClass | — | 🟠 hub |
Derivation notes
Matched by filename substring (no annotation; substrate-derived):
ad-thermodynamics-from-z.mdising-cft-magnetic-perturbation.mdising-cft-primary-operators.mdising-scaling-relations.mdkramers-wannier-duality.mdtransfer-matrix-symmetric-split.md
References
Papers cited by this model's @register cards. The full numbered list is on the Reference List.
- [42]
- L. Onsager. Crystal Statistics. I. A Two-Dimensional Model with an Order-Disorder Transition. Physical Review 65, 117–149 (1944).
- [91]
- C. N. Yang. The Spontaneous Magnetization of a Two-Dimensional Ising Model. Physical Review 85, 808–816 (1952).