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All instances / Electron gas, 2D

Electron gas, 2D square cell, N = 90, rs = 30, unpolarized

Record

-0.031919(1) E/N (Ha)

Fixed-node DMC (Jastrow optimised at Gamma, start 1)

10.1103/PhysRevB.110.245145 · lowest unflagged energy published, a projected estimate (rules §6)

The Hamiltonian

H = −½ ∑i ∇i2 + ∑i<j vE(ri − rj) + Nξ/2

Homogeneous electron gas in 2D: N↑ = 45, N↓ = 45 in a periodic square cell at rs = 30 bohr, Γ point. vE is the Ewald-summed Coulomb interaction with a uniform neutralizing background, ξ the Madelung term. Hartree atomic units; the energy per electron is E/N.

cell
square
electrons
90
boundary
periodic
N_up
45
N_dn
45
rs
30
twist
Gamma
energies
7

Stored as a total energy in Hartree (rules §12); quoted here as E/N (Ha), the energy per electron (how the conversion works).

Every published energy

Grouped by what the number is. Where the instance is not solved, the lowest unflagged energy of any group is the record.

Strict variational upper bounds (3)

Where the instance is not solved, the record is the lowest unflagged energy in this group or among the projected and extrapolated ones, with or without an error bar; where it is solved, the exact energy is the record and the lowest of these is the closest challenger.

E/N (Ha)distance to recordσVar(E)V-score methodsourceyear
-0.0317373 1.8e-4 2.0e-7 n/a n/a Slater-Jastrow (Jastrow optimised at Gamma from random starting point 1)
peer reviewed
10.1103/PhysRevB.110.245145 n/a
-0.0271506 4.8e-3 7.0e-7 n/a n/a Slater-Jastrow (Jastrow optimised at Gamma from random starting point 3)
peer reviewed
10.1103/PhysRevB.110.245145 n/a
-0.0251398 6.8e-3 8.0e-7 n/a n/a Slater-Jastrow (Jastrow optimised at Gamma from random starting point 2)
peer reviewed
10.1103/PhysRevB.110.245145 n/a

Projected or fixed-node estimates (4)

Variational only within a constraint: fixed-node, constrained-path, GFMC on a trial state. Node- or constraint-dependent, so not cleanly comparable to each other or to strict bounds. Like any unflagged energy, one holds the record where it is the lowest on an unsolved instance.

E/N (Ha)distance to recordσVar(E)V-score methodsourceyear
-0.031919record 0 1.0e-6 n/a n/a Fixed-node DMC (Jastrow optimised at Gamma, start 1)
peer reviewed
10.1103/PhysRevB.110.245145 n/a
-0.03151 4.1e-4 2.0e-5 n/a n/a Fixed-node DMC (HF nodes; twist Gamma)
peer reviewed
10.1103/PhysRevB.110.245145 n/a
-0.02848 3.4e-3 2.0e-5 n/a n/a Fixed-node DMC (Jastrow optimised at Gamma, start 3)
peer reviewed
10.1103/PhysRevB.110.245145 n/a
-0.02676 5.2e-3 7.0e-5 n/a n/a Fixed-node DMC (Jastrow optimised at Gamma, start 2)
peer reviewed
10.1103/PhysRevB.110.245145 n/a

How these numbers were read

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

-0.031919(1) — Fixed-node DMC (Jastrow optimised at Gamma, start 1)

Checked 2026-10-19 · source text of arXiv:2405.00425 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. −0.031919(1)

Table IV, Γ start 1, column SJ-DMC; sources/2405.00425.txt line 387; printed in Ha per electron; version read: arXiv text in sources/; journal copy not read | Table III (txt lines 371-376): the HF energy for the 90-electron square cell at rs=30 and Gamma is printed as -0.0196518 Ha/el. QMBL's own checks/heg-hf/hf.mjs (2 square 45 45 30, Gamma) gives -0.0196517776 (Ewald sum, uniform background, Madelung term included), so Hartree units, per electron and Ewald with Madelung included are fixed by that number. No sentence in the text names the Ewald sum or the Madelung term. Fig. 4 caption (txt line 505) subtracts 'the Madelung energy of a hexagonal lattice, -vM0/rs' from DMC energies, consistent with energies that contain the Madelung term. The Balder

-0.0317373(2) — Slater-Jastrow (Jastrow optimised at Gamma from random...

Checked 2026-10-19 · source text of arXiv:2405.00425 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. −0.0317373(2)

Table III, Γ start 1, column SJ-VMC; sources/2405.00425.txt line 371; printed in Ha per electron; version read: arXiv text in sources/; journal copy not read | Table III (txt lines 371-376): the HF energy for the 90-electron square cell at rs=30 and Gamma is printed as -0.0196518 Ha/el. QMBL's own checks/heg-hf/hf.mjs (2 square 45 45 30, Gamma) gives -0.0196517776 (Ewald sum, uniform background, Madelung term included), so Hartree units, per electron and Ewald with Madelung included are fixed by that number. No sentence in the text names the Ewald sum or the Madelung term. Fig. 4 caption (txt line 505) subtracts 'the Madelung energy of a hexagonal lattice, -vM0/rs' from DMC energies, consistent with energies that contain the Madelung term. The Balder

-0.03151(2) — Fixed-node DMC (HF nodes; twist Gamma)

Checked 2026-10-19 · source text of arXiv:2405.00425 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. −0.03151(2)

Table IV, Γ start 1, column S-DMC; sources/2405.00425.txt line 387; printed in Ha per electron; version read: arXiv text in sources/; journal copy not read | Table III (txt lines 371-376): the HF energy for the 90-electron square cell at rs=30 and Gamma is printed as -0.0196518 Ha/el. QMBL's own checks/heg-hf/hf.mjs (2 square 45 45 30, Gamma) gives -0.0196517776 (Ewald sum, uniform background, Madelung term included), so Hartree units, per electron and Ewald with Madelung included are fixed by that number. No sentence in the text names the Ewald sum or the Madelung term. Fig. 4 caption (txt line 505) subtracts 'the Madelung energy of a hexagonal lattice, -vM0/rs' from DMC energies, consistent with energies that contain the Madelung term. The Balder

-0.02848(2) — Fixed-node DMC (Jastrow optimised at Gamma, start 3)

Checked 2026-10-19 · source text of arXiv:2405.00425 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. −0.02848(2)

Table IV, Γ start 3, column SJ-DMC; sources/2405.00425.txt line 389; printed in Ha per electron; version read: arXiv text in sources/; journal copy not read | Table III (txt lines 371-376): the HF energy for the 90-electron square cell at rs=30 and Gamma is printed as -0.0196518 Ha/el. QMBL's own checks/heg-hf/hf.mjs (2 square 45 45 30, Gamma) gives -0.0196517776 (Ewald sum, uniform background, Madelung term included), so Hartree units, per electron and Ewald with Madelung included are fixed by that number. No sentence in the text names the Ewald sum or the Madelung term. Fig. 4 caption (txt line 505) subtracts 'the Madelung energy of a hexagonal lattice, -vM0/rs' from DMC energies, consistent with energies that contain the Madelung term. The Balder

-0.0271506(7) — Slater-Jastrow (Jastrow optimised at Gamma from random...

Checked 2026-10-19 · source text of arXiv:2405.00425 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. −0.0271506(7)

Table III, Γ start 3, column SJ-VMC; sources/2405.00425.txt line 373; printed in Ha per electron; version read: arXiv text in sources/; journal copy not read | Table III (txt lines 371-376): the HF energy for the 90-electron square cell at rs=30 and Gamma is printed as -0.0196518 Ha/el. QMBL's own checks/heg-hf/hf.mjs (2 square 45 45 30, Gamma) gives -0.0196517776 (Ewald sum, uniform background, Madelung term included), so Hartree units, per electron and Ewald with Madelung included are fixed by that number. No sentence in the text names the Ewald sum or the Madelung term. Fig. 4 caption (txt line 505) subtracts 'the Madelung energy of a hexagonal lattice, -vM0/rs' from DMC energies, consistent with energies that contain the Madelung term. The Balder

-0.02676(7) — Fixed-node DMC (Jastrow optimised at Gamma, start 2)

Checked 2026-10-19 · source text of arXiv:2405.00425 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. −0.02676(7)

Table IV, Γ start 2, column SJ-DMC; sources/2405.00425.txt line 388; printed in Ha per electron; version read: arXiv text in sources/; journal copy not read | Table III (txt lines 371-376): the HF energy for the 90-electron square cell at rs=30 and Gamma is printed as -0.0196518 Ha/el. QMBL's own checks/heg-hf/hf.mjs (2 square 45 45 30, Gamma) gives -0.0196517776 (Ewald sum, uniform background, Madelung term included), so Hartree units, per electron and Ewald with Madelung included are fixed by that number. No sentence in the text names the Ewald sum or the Madelung term. Fig. 4 caption (txt line 505) subtracts 'the Madelung energy of a hexagonal lattice, -vM0/rs' from DMC energies, consistent with energies that contain the Madelung term. The Balder

-0.0251398(8) — Slater-Jastrow (Jastrow optimised at Gamma from random...

Checked 2026-10-19 · source text of arXiv:2405.00425 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. −0.0251398(8)

Table III, Γ start 2, column SJ-VMC; sources/2405.00425.txt line 372; printed in Ha per electron; version read: arXiv text in sources/; journal copy not read | Table III (txt lines 371-376): the HF energy for the 90-electron square cell at rs=30 and Gamma is printed as -0.0196518 Ha/el. QMBL's own checks/heg-hf/hf.mjs (2 square 45 45 30, Gamma) gives -0.0196517776 (Ewald sum, uniform background, Madelung term included), so Hartree units, per electron and Ewald with Madelung included are fixed by that number. No sentence in the text names the Ewald sum or the Madelung term. Fig. 4 caption (txt line 505) subtracts 'the Madelung energy of a hexagonal lattice, -vM0/rs' from DMC energies, consistent with energies that contain the Madelung term. The Balder

Coverage

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