QEncode Benchmark
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H2

/bravyi kitaev/hea
Certified
Beats CCSD(T)
cc-pvdz

H2_ccpvdz_BK_HEA_v4_tapered__sha256_6e206ec6f1f02ea4

VQE Gap

1.8946e-10 Ha

CASCI ref

-1.131287 Ha

Qubits (tapered)

1

CCSD(T) corr.

-3.459e-2 Ha

Molecule / Problem

NameH2
Basis setcc-pvdz
GeometryH 0.0 0.0 0.0; H 0.0 0.0 0.735
Charge0
Spin0
Active electrons2
Active orbitals2
Orbital optimizationHF

Encoding / Circuit

Qubit mappingbravyi-kitaev
Ansatz typehea
Ansatz reps (HEA)2
TaperingZ2 symmetry — 3 symmetries removed
Qubits (original)4
Qubits (tapered)1
Num parameters3
Circuit depth4
2Q gates0

Energy Results

HF energy-1.1286227699 Ha
MP2 energy-1.1549489623 Ha
CCSD energy-1.1632095636 Ha
CCSD(T) energy-1.1632095636 Ha
CASCI ground state-1.1312865113 Ha
VQE best energy-1.1312865111 Ha
|VQE − CASCI| gap1.894618e-10 Ha
CCSD(T) correlation-3.458679e-2 Ha

Optimizer / Run Config

AlgorithmCOBYLA
Multistart runs10
Max iterations500
Total func evals399
Num parameters3
Backenddefault.qubit

Provenance / Reproducibility

Entry IDH2_ccpvdz_BK_HEA_v4_tapered__sha256_6e206ec6f1f02ea4
Schema version4.0.0
Created (UTC)2026-07-15T13:22:20.975238+00:00
SHA-256 hash6e206ec6f1f02ea476c8882f53e9939b42dda9b62eeb85730535c3333f55677f
Python3.11.15
PySCF2.6.2
PennyLane0.45.0
OpenFermion1.6.1
NumPy2.2.6
SciPy1.13.1

Reproduce this result

# Clone repo and install pinned environment

git clone https://github.com/qencode-benchmark/qencode-benchmark

cd qencode-benchmark

pip install -r requirements-v4.txt

# Run this entry

python scripts/generate_entry_v4.py \

--molecule H2 \

--mapping bravyi_kitaev \

--ansatz-type hea \

--reps 2 \

--multistart 10 \

--max-iter 500 \

--out-dir releases/v4/db

View raw JSON on GitHub