Hubbard chain, 14 sites, U = 1.66810054, n ≈ 0.5714

Hubbard/chain_14_P_4_1.66810054

No record

—

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

The Hamiltonian

H = −t ∑_⟨ij⟩,σ (c^†_iσc_jσ + h.c.) + U ∑_i n_i↑n_i↓

t = 1, U = 1.66810054, N_↑ = N_↓ = 4 on 14 sites.

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

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

Zero-variance, bond-dimension or Trotter-error extrapolations. Not a bound: no ansatz ever reached the number, so it cannot hold the record.

E/site	σ	Var(E)	V-score	method	source	year
-0.8761535	n/a	3.42e-8	1.4e-9	DMRG (maxbonddim = 1550, extrapolated energy -12.266149729 +/- 5E-8) VarBench reference run	run script, no paper cited	n/a

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

E/site	σ	Var(E)	V-score	method	source	year
-0.8761535	n/a	n/a	n/a	Exact diagonalization VarBench reference run	run script, no paper cited	n/a

No row here carries a publication year. Nothing has been added to this instance since the VarBench snapshot of 2024-10-22.