Entry BeH2_ccpvdz_JW_HEA_v4_tapered__sha256_3a0217702318b7e5 | QEncode

VQE Gap

5.4250e-8 Ha

CASCI ref

-15.768411 Ha

Qubits (tapered)

CCSD(T) corr.

-6.896e-2 Ha

Molecule / Problem

NameBeH2

Basis setcc-pvdz

GeometryH 0.0 0.0 -1.30; Be 0.0 0.0 0.0; H 0.0 0.0 1.30

Charge0

Spin0

Active electrons4

Active orbitals4

Orbital optimizationHF

Encoding / Circuit

Qubit mappingjordan-wigner

Ansatz typehea

Ansatz reps (HEA)2

TaperingZ2 symmetry — 5 symmetries removed

Qubits (original)8

Qubits (tapered)3

Num parameters9

Circuit depth8

2Q gates4

Energy Results

HF energy-15.7664276149 Ha

MP2 energy-15.8183028207 Ha

CCSD energy-15.8349590260 Ha

CCSD(T) energy-15.8353910120 Ha

CASCI ground state-15.7684109880 Ha

VQE best energy-15.7684109338 Ha

|VQE − CASCI| gap5.425010e-8 Ha

CCSD(T) correlation-6.896340e-2 Ha

Optimizer / Run Config

AlgorithmCOBYLA

Multistart runs1

Max iterations500

Total func evals223

Num parameters9

Backenddefault.qubit

Provenance / Reproducibility

Entry IDBeH2_ccpvdz_JW_HEA_v4_tapered__sha256_3a0217702318b7e5

Schema version4.0.0

Created (UTC)2026-07-15T13:20:19.501388+00:00

SHA-256 hash3a0217702318b7e5ca6d666026e5ad6cd043c66347f9d156b1ea8a7511a0d692

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 BeH2 \

--mapping jordan_wigner \

--ansatz-type hea \

--reps 2 \

--multistart 1 \

--max-iter 500 \

--out-dir releases/v4/db

View raw JSON on GitHub