Quantum Many-Body Harness

Benchmarks

Every method family measured on every exactly solvable model: 70 combinations — 51 completed, 17 unsuitable, 2 failed. Each completed entry is the largest size that method reached within the compute budget, with its relative error against the exact solution.

Benchmark — largest size each method reached within 100 CPU core-hours per run; relative error vs the exact solution at that size. Accuracy bar: 10-8 for deterministic routes, 10-3 for variational, 2σ for stochastic; entries above their bar report the method's intrinsic limit at this size (2026-07).

✓ completed — largest size · relative error (hover for the measured observable)   ∅ unsuitable — the method cannot express this model (hover for why)   ✗ failed — the software route broke (largest size attempted).

model \ methodedmpspepsltrgmcrgqmcvmcmfpolyoptqcs
tfim-chain (L sites)34 · 1.4×10-12256 · 3.7×10-121.0×106 · 3.4×10-59 · 0.22128 · 6.0×10-5128 · 0.00341.1×109 · 0.0181.1×105 · 0.571024 · 0.0085
ising-2d-onsager (L (L×L))5 · 0.0024160 · 2.1×10-41024 · 0.0026561 · 9.8×10-4256 · 0.001632 768 · 0.764
toric-code (L (L×L, 2L² qubits))5 · 6.9×10-129 · 5.5×10-12 · 2.2×10-1628 · 3.2×10-145 · 0.03588 000 · 0.5112 · 1.1×10-10576 · 0
aklt-chain (L sites)20 · 5.0×10-16 · 1.7×10-16 · 1.6×10-151.1×109 · 1.8×10-816 · 0.04616 · 0.0783.2×109 · 0.532 768 · 0.1216 384 · 1.2×10-14
hubbard-1d-lieb-wu (L sites)20 · 0.0027256 · 2.7×10-68192 · 0.0084254 · 0.0021242.2×1012 · 0.1816 384 · 2.514 · 0.25
lmg (N spins)109 · 01.3×105 · 1.9×10-123.0×105 · 2.4×10-516 384 · 1.7×10-82.5×1010 · 8.6×10-121011 · 1.4×10-114.3×108 · 3.3×10-11
kicked-ising-floquet (L qubits)18 · 0.013 · 1.4×10-15∞ (t=11) · 3.2×10-11760 · 1.1×10-13109 · 3.1×10-6

Frontier figure — each point is one completed model × method entry: the largest size reached within the compute budget (x) against the relative error at that size (y); color = method, shape = model. The x axis converts each model's size to the log₂ of its Hilbert-space dimension: L (TFIM chain, kicked Ising), 1.58 L (AKLT, 3 states per site), 2 L (Hubbard), L² (2D Ising, classical configurations), 2 L² (toric code), N (LMG). Entries that reached the infinite-size limit sit in the ∞ band past the axis break; points on the bottom edge are machine-exact (error 0). The dashed lines mark the deterministic (10-8) and variational (10-3) accuracy bars; the stochastic bar — agreement with the exact value within 2σ of the run's own statistical error bar — is a per-point criterion and has no fixed level to draw.

edmpspepsltrgmcrgqmcvmcmfpolyoptqcstfim-chaintfim-chainising-2d-onsagerising-2d-onsagertoric-codetoric-codeaklt-chainaklt-chainhubbard-1d-lieb-wuhubbard-1d-lieb-wulmglmgkicked-ising-floquetkicked-ising-floquet100101102103104105106107108109101010111012101310-1610-1410-1210-1010-810-610-410-2100deterministic barvariational barlog₂ Hilbert-space dimensionrelative error at the frontieraklt-chain — ed: size 20 L sites, rel. error 5e-16aklt-chain — ltrg: size 1073741824 L sites, rel. error 1.8e-08aklt-chain — mf: size 3200000000 L sites, rel. error 0.5aklt-chain — polyopt: size 32768 L sites, rel. error 0.12aklt-chain — qcs: size 16384 L sites, rel. error 1.2e-14aklt-chain — qmc: size 16 L sites, rel. error 0.046aklt-chain — vmc: size 16 L sites, rel. error 0.078hubbard-1d-lieb-wu — ed: size 20 L sites, rel. error 0.0027hubbard-1d-lieb-wu — ltrg: size 8192 L sites, rel. error 0.0084hubbard-1d-lieb-wu — mf: size 2200000000000 L sites, rel. error 0.18hubbard-1d-lieb-wu — mps: size 256 L sites, rel. error 2.7e-06hubbard-1d-lieb-wu — polyopt: size 16384 L sites, rel. error 2.5hubbard-1d-lieb-wu — qcs: size 14 L sites, rel. error 0.25hubbard-1d-lieb-wu — qmc: size 254 L sites, rel. error 0.0021ising-2d-onsager — ed: size 5 L (L×L), rel. error 0.0024ising-2d-onsager — ltrg: size 1024 L (L×L), rel. error 0.002ising-2d-onsager — mcrg: size 6561 L (L×L), rel. error 0.00098ising-2d-onsager — mf: size 32768 L (L×L), rel. error 0.76ising-2d-onsager — peps: size 160 L (L×L), rel. error 0.00021ising-2d-onsager — qmc: size 256 L (L×L), rel. error 0.0016kicked-ising-floquet — ed: size 18 L qubits, rel. error 0.013kicked-ising-floquet — mf: size 760 L qubits, rel. error 1.1e-13kicked-ising-floquet — qcs: size 1000000000 L qubits, rel. error 3.1e-06lmg — ed: size 1000000000 N spins, rel. error 0 (machine-exact)lmg — mf: size 25000000000 N spins, rel. error 8.6e-12lmg — mps: size 131072 N spins, rel. error 1.9e-12lmg — polyopt: size 100000000000 N spins, rel. error 1.4e-11lmg — qcs: size 429000000 N spins, rel. error 3.3e-11lmg — qmc: size 300000 N spins, rel. error 2.4e-05lmg — vmc: size 16384 N spins, rel. error 1.7e-08tfim-chain — ed: size 34 L sites, rel. error 1.4e-12tfim-chain — ltrg: size 1048576 L sites, rel. error 3.4e-05tfim-chain — mcrg: size 9 L sites, rel. error 0.22tfim-chain — mf: size 1073741824 L sites, rel. error 0.018tfim-chain — mps: size 256 L sites, rel. error 3.7e-12tfim-chain — polyopt: size 114688 L sites, rel. error 0.57tfim-chain — qcs: size 1024 L sites, rel. error 0.0085tfim-chain — qmc: size 128 L sites, rel. error 6e-05tfim-chain — vmc: size 128 L sites, rel. error 0.0034toric-code — ed: size 5 L (L×L, 2L² qubits), rel. error 6.9e-12toric-code — ltrg: size 28 L (L×L, 2L² qubits), rel. error 3.2e-14toric-code — mf: size 88000 L (L×L, 2L² qubits), rel. error 0.5toric-code — mps: size 9 L (L×L, 2L² qubits), rel. error 5.5e-12toric-code — polyopt: size 112 L (L×L, 2L² qubits), rel. error 1.1e-10toric-code — qcs: size 576 L (L×L, 2L² qubits), rel. error 0 (machine-exact)toric-code — vmc: size 5 L (L×L, 2L² qubits), rel. error 0.035aklt-chain — mps: size ∞, rel. error 1.7e-16aklt-chain — peps: size ∞, rel. error 1.6e-15kicked-ising-floquet — mps: size ∞, rel. error 1.4e-15kicked-ising-floquet — peps: size ∞ (t=11), rel. error 3.2e-11toric-code — peps: size ∞, rel. error 2.2e-16