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All instances / Hubbard

Hubbard square 16x16, U = 8, n = 0.875

Best values (rules §6)

best variational -0.75865(3) VAFQMC
Wu et al. (2024) · the lowest unflagged variational energy, a strict variational bound
best projected -0.7583 FN-GFMC (ACE)
Gu et al. (2026) · the lowest unflagged projected energy, a projected estimate, which depends on its node or constraint

Energies as E/site. Classes are different claims and are not ranked against each other.

The Hamiltonian

H = −t ∑⟨ij⟩,σ (c†iσcjσ + h.c.) + U ∑i ni↑ni↓

t = 1, U = 8, N↑ = N↓ = 112 on 256 sites.

lattice
square
sites
256
boundary
periodic
Nf
112
U
8
energies
18

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

Every published energy

Grouped by what the number is. The exact energy comes first where there is one; in every other group the lowest unflagged energy is its best value, and each row's distance is to that best (rules §6).

Strict variational upper bounds (14)

Energies that a variational state reached (VMC, DMRG and MPS at finite bond dimension, PEPS, NQS, VQE). Each is an upper bound on the ground-state energy.

E/sitedistance to class bestσVar(E)V-score methodsourcecodeyearcomment
-0.75865best variational 0 2.7e-5 1.50e+0 9.8e-4 VAFQMC Wu et al. (2024) 2024
-0.7573 1.4e-3 n/a n/a n/a VMC (ACE)
peer reviewed
Gu et al. (2026) uses LaQX 2026
-0.7563 2.4e-3 n/a n/a n/a VMC (transformer BF)
peer reviewed
Gu et al. (2026) bytedance/laqx 2026
-0.7552 3.5e-3 n/a n/a n/a VMC (tensor BF)
peer reviewed
Liang (2025) 2025
-0.7543 4.4e-3 2.0e-4 n/a n/a VMC (residual HB)
preprint
Zhou et al. (2026) 2026
-0.7529 5.8e-3 n/a n/a n/a VMC (SCALE)
peer reviewed
Gu et al. (2026) uses LaQX 2026
-0.7526 6.1e-3 n/a n/a n/a VMC (HB)
preprint
Zhou et al. (2026) 2026
-0.7515 7.2e-3 1.0e-4 1.63e+1 1.1e-2 VMC (HFPS)
preprint
Roth et al. (2025) uses Quantax 2025
-0.751 7.7e-3 n/a n/a n/a VMC (HB)
preprint
Zhou et al. (2026) 2026
-0.7509 7.8e-3 n/a n/a n/a VMC (tensor BF)
peer reviewed
Liang (2025) 2025
-0.74885 9.8e-3 1.6e-5 1.52e+1 1.0e-2 VMC (Jastrow + BF)
VarBench reference run
Wu et al. (2024) run script 2024
-0.74395 1.5e-2 3.1e-5 2.66e+1 1.8e-2 VMC (Jastrow + BF)
VarBench reference run
Wu et al. (2024) run script 2024
-0.7401 1.9e-2 1.0e-4 2.01e+1 1.3e-2 VMC (HFPS)
preprint
Roth et al. (2025) uses Quantax 2025
-0.7271 3.2e-2 3.0e-4 3.71e+1 2.5e-2 VMC (HFPS)
preprint
Roth et al. (2025) uses Quantax 2025

Projected or fixed-node estimates (4)

Variational only within a constraint: fixed-node, constrained-path, GFMC on a trial state. Each depends on its node or constraint, so two of them are not cleanly comparable to each other or to strict bounds.

E/sitedistance to class bestσVar(E)V-score methodsourcecodeyearcomment
-0.7583best projected 0 n/a n/a n/a FN-GFMC (ACE)
peer reviewed
Gu et al. (2026) 2026
-0.756 2.3e-3 n/a n/a n/a FN-GFMC (SCALE)
peer reviewed
Gu et al. (2026) 2026
-0.75438 3.9e-3 3.9e-5 n/a n/a FN-GFMC (Jastrow + BF)
VarBench reference run
Wu et al. (2024) run script 2024
-0.74991 8.4e-3 2.7e-5 n/a n/a FN-GFMC (Jastrow + BF)
VarBench reference run
Wu et al. (2024) run script 2024

How these numbers were read

Where each number below was read, and how it was checked.

-0.7583, FN-GFMC (ACE)

Checked 2026-09-10 · source text/table parsed locally (arXiv HTML or pypdf), no LLM transcription

Reported as. -0.7583 per site

Read directly from the Table 1 HTML of arXiv:2604.25775, column t'=0 PBC (16x16, U=8, delta=1/8). ACE Table 1 energies are WITHOUT symmetry projection (Sec. III.C.2), so they are not the ansatz floor.

-0.7573, VMC (ACE)

Checked 2026-09-10 · source text/table parsed locally (arXiv HTML or pypdf), no LLM transcription

Reported as. -0.7573 per site

Read directly from the Table 1 HTML of arXiv:2604.25775, column t'=0 PBC (16x16, U=8, delta=1/8). ACE Table 1 energies are WITHOUT symmetry projection (Sec. III.C.2), so they are not the ansatz floor.

-0.7563, VMC (transformer BF)

Checked 2026-09-10 · source text/table parsed locally (arXiv HTML or pypdf), no LLM transcription

Reported as. -0.7563 per site

Read directly from the Table 1 HTML of arXiv:2604.25775, column t'=0 PBC (16x16, U=8, delta=1/8). ACE Table 1 energies are WITHOUT symmetry projection (Sec. III.C.2), so they are not the ansatz floor.

-0.756, FN-GFMC (SCALE)

Checked 2026-09-10 · source text/table parsed locally (arXiv HTML or pypdf), no LLM transcription

Reported as. -0.756 per site

Read directly from the Table 1 HTML of arXiv:2604.25775, column t'=0 PBC (16x16, U=8, delta=1/8). ACE Table 1 energies are WITHOUT symmetry projection (Sec. III.C.2), so they are not the ansatz floor.

-0.7552, VMC (tensor BF)

Checked 2026-09-10 · source text/table parsed locally (arXiv HTML or pypdf), no LLM transcription

Reported as. -0.7552 per site

Primary located 2026-09-15: Table I of arXiv:2507.01856, n = 0.875, U = 8, 16x16 PBC, column Ep = 1 (one Lanczos step). First found quoted in Table 1 of arXiv:2604.25775 as Tensor-Backflow+Lanczos [21].

-0.7543(2), VMC (residual HB)

Checked 2026-09-15 · source text of arXiv:2606.00924 read locally (arXiv HTML or pypdf layout text); value copied from the harvested cell and the text, no LLM transcription of numbers; single reading

Reported as. −0.7543(2)

main text, 'On the 16x16 lattice at nh=1/8 and U=8, RHB with the FNN yields...' | same instance as above

-0.7529, VMC (SCALE)

Checked 2026-09-10 · source text/table parsed locally (arXiv HTML or pypdf), no LLM transcription

Reported as. -0.7529 per site

Read directly from the Table 1 HTML of arXiv:2604.25775, column t'=0 PBC (16x16, U=8, delta=1/8). ACE Table 1 energies are WITHOUT symmetry projection (Sec. III.C.2), so they are not the ansatz floor.

-0.7526, VMC (HB)

Checked 2026-09-15 · source text of arXiv:2606.00924 read locally (arXiv HTML or pypdf layout text); value copied from the harvested cell and the text, no LLM transcription of numbers; single reading

Reported as. −0.7526

main text, same paragraph | same instance as above

-0.7515(1), VMC (HFPS)

Checked 2026-09-10 · source text/table parsed locally (arXiv HTML or pypdf), no LLM transcription

Reported as. -0.7515 (+/- 0.0001) per site

Read directly from the Table 1 HTML of arXiv:2604.25775, column t'=0 PBC (16x16, U=8, delta=1/8). ACE Table 1 energies are WITHOUT symmetry projection (Sec. III.C.2), so they are not the ansatz floor.

-0.751, VMC (HB)

Checked 2026-09-15 · source text of arXiv:2606.00924 read locally (arXiv HTML or pypdf layout text); value copied from the harvested cell and the text, no LLM transcription of numbers; single reading

Reported as. −0.7510

main text, same paragraph | same instance as above

-0.7509, VMC (tensor BF)

Checked 2026-09-10 · source text/table parsed locally (arXiv HTML or pypdf), no LLM transcription

Reported as. -0.7509 per site

Primary located 2026-09-15: Table I of arXiv:2507.01856, n = 0.875, U = 8, 16x16 PBC, column Ep = 0. First found quoted in Table 1 of arXiv:2604.25775 as Tensor-Backflow [21].

-0.7401(1), VMC (HFPS)

Checked 2026-10-16 · source text of arXiv:2511.07566 read locally (arXiv HTML or pypdf layout text); value copied from the harvested cell and the text, no LLM transcription of numbers; single reading

Reported as. -0.7401(1)

Table V (App. D 'Supplementary data': 256-site 16x16 cluster, U=8, delta=1/8; columns Filled Stripe | Half-filled stripe + No SC | Half-filled stripe + SC); row t'=0.0, column Half-filled stripe + SC; sources/2511.07566.txt line 1198; version read: arXiv v1 (sources/2511.07566.txt); no journal version (Crossref, arXiv abs page); qmbl-verify 2026-10-19 SP8-heg3d-hubbard-heg2d-heisenberg#75: energy_variance null -> 20.06528 (Energy -0.7401(1) (Table V (txt lines 1193-1200; 'Energy per site of competing phases on a 256 site'), row t′ = 0.0, column Half-filled stripe + SC) and sigma are right (-0.7401 x 256 = -189.4656 (sto) | Eq. (1): H = U sum n_up n_dn - sum t_xx' c+c, t_xx' = t' on next-nearest bonds, periodic; Table V: 16x16, U = 8, doping 1/8, energy per site. The d-wave field Delta_0 enters only the mean-field Hamiltonian of the initial orbitals (Eq. 5, App. D).

-0.7271(3), VMC (HFPS)

Checked 2026-10-16 · source text of arXiv:2511.07566 read locally (arXiv HTML or pypdf layout text); value copied from the harvested cell and the text, no LLM transcription of numbers; single reading

Reported as. -0.7271(3)

Table V (App. D 'Supplementary data': 256-site 16x16 cluster, U=8, delta=1/8; columns Filled Stripe | Half-filled stripe + No SC | Half-filled stripe + SC); row t'=0.0, column Half-filled stripe + No SC; sources/2511.07566.txt line 1198; version read: arXiv v1 (sources/2511.07566.txt); no journal version (Crossref, arXiv abs page); qmbl-verify 2026-10-19 SP8-heg3d-hubbard-heg2d-heisenberg#74: energy_variance null -> 37.12 (Energy -0.7271(3) (Table V (txt lines 1193-1200; 'Energy per site of competing phases on a 256 site'), row t′ = 0.0, column Half-filled stripe + No SC) and sigma are right (-0.7271 x 256 = -186.1376 () | Eq. (1): H = U sum n_up n_dn - sum t_xx' c+c, t_xx' = t' on next-nearest bonds, periodic; Table V: 16x16, U = 8, doping 1/8, energy per site. The d-wave field Delta_0 enters only the mean-field Hamiltonian of the initial orbitals (Eq. 5, App. D).

Coverage

Newest published number here: 2026. Literature last checked 2026-09-15 (citation screen of Sorella 2023 (PRB 107, 115133), VAFQMC doping scan: citing works from OpenAlex and Semantic Scholar (scripts/cited_by.mjs)): 8 papers read, 1 of them with an energy on this page.

This instance as data

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