This computes the ground-state energy of the antiferromagnetic Heisenberg open spin chain by exact diagonalization / Lanczos, cross-checked against an algorithmically independent oracle. It runs entirely in your browser - no install, deterministic - so you can reproduce a small-N reference before committing it to an HPC run. GDBS is a bridge to HPC, not a surrogate for it.
Multi-seed Lanczos with an independent power-iteration oracle finds the Heisenberg open-chain ground state. N=2 singlet -0.75 (exact -3J/4); N=4 -1.6160254 (< 1e-4 vs Bethe ansatz); N=10 -4.258 (< 1e-2 vs the literature singlet). Oracle and Lanczos agree to < 1e-10.
The ground state is found by multi-seed Lanczos iteration on the Heisenberg open-chain Hamiltonian. An algorithmically independent oracle - dense Jacobi diagonalization for small N, shifted power iteration for sparse cases - is run alongside as a cross-check. The oracle and the Lanczos result agree to < 1e-10, so the reported energy is not an artifact of a single algorithm.
Verified results: N=2 reproduces the singlet at -0.75 (exact -3J/4); N=4 gives -1.6160254 (< 1e-4 vs the Bethe ansatz); N=10 gives -4.258 (< 1e-2 vs the literature singlet).
This is exact diagonalization / Lanczos with an algorithmically independent oracle cross-check: an honest small-N reproduction. The reported energies are reproductions of published / analytic references at small N, not an extrapolation to the thermodynamic limit.
Open the engine and run it deterministically in your browser:
Open lattice / spin systems (DMRG) in GDBS See the full validation table