Heisenberg kagome 2x2 (12 sites)

Heisenberg/kagome-2x2_12_P

No record

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solved exactly (rules §6). Every row is still listed below.

The Hamiltonian

H = ∑_⟨ij⟩ σ_i·σ_j

Nearest-neighbour Heisenberg antiferromagnet, J = 1, written with Pauli matrices.

lattice: kagome-2x2
sites: 12
boundary: periodic
energies: 1

Stored as a total energy in the convention of VarBench; quoted here as E/N (S.S), which is what the papers report (how the conversion works).

Every published energy

Grouped by what the number is. Ranking happens only inside the first group.

Numerically exact (1)

Exact diagonalization, an exact solution, or sign-problem-free QMC where that is established: the answer, not a claim about it.

E/N (S.S)	σ	Var(E)	V-score	method	source	year
-0.4537396	n/a	n/a	n/a	Exact diagonalization (Lanczos) peer reviewed	Lauchli, Sudan & Sorensen, Groun	n/a

How these numbers were read

Rows added after the VarBench import record where the number came from.

-0.4537396 — Exact diagonalization (Lanczos)

Checked 2026-09-15 · arXiv PDF extracted locally with pypdf in layout mode, parsed by column position and checked against the paper's own per-site column; no LLM transcription

Reported as. Total E = -5.444875216 (S.S), cluster 12

Table I, "Cluster studied in this work", row N = 12: basis vectors a = (2,0), b = (0,2) in units of the kagome lattice vectors a1, a2 (each of length 2a), periodic (torus). E/N = -0.453740 as printed in the table's own E/N column; Pauli total = 4 E. The (2,0),(0,2) cluster is 2 x 2 unit cells, kagome-2x2 in the VarBench naming.

Coverage

No row here carries a publication year. 1 row added from the 2026-09 literature sweep, on top of the VarBench snapshot of 2024-10-22.

This instance as data

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