Hubbard square 6x6, U = 4, n ≈ 0.6667

The Hamiltonian

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

t = 1, U = 4, N_↑ = N_↓ = 12 on 36 sites.

lattice

square

sites

36

boundary

periodic

Nf

12

U

4

energies

1

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).