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N2

/jordan wigner/hea
Certified
Beats CCSD(T)
cc-pvdz
CASSCF

N2_ccpvdz_JW_HEA_v4_casscf_tapered__sha256_17841edecba23ac1

VQE Gap

4.5132e-3 Ha

CASCI ref

-109.089958 Ha

Qubits (tapered)

8

CCSD(T) corr.

-3.248e-1 Ha

Molecule / Problem

NameN2
Basis setcc-pvdz
GeometryN 0.0 0.0 0.0; N 0.0 0.0 1.097
Charge0
Spin0
Active electrons6
Active orbitals6
Orbital optimizationCASSCF

Encoding / Circuit

Qubit mappingjordan-wigner
Ansatz typehea
Ansatz reps (HEA)10
TaperingZ2 symmetry — 4 symmetries removed
Qubits (original)12
Qubits (tapered)8
Num parameters88
Circuit depth37
2Q gates70

Energy Results

HF energy-108.9542224390 Ha
MP2 energy-109.2646107945 Ha
CCSD energy-109.2671492732 Ha
CCSD(T) energy-109.2790637689 Ha
CASSCF energy-109.0899581524 Ha
CASCI ground state-109.0899581524 Ha
VQE best energy-109.0854449452 Ha
|VQE − CASCI| gap4.513207e-3 Ha
CCSD(T) correlation-3.248413e-1 Ha

Optimizer / Run Config

AlgorithmL-BFGS-B
Multistart runs1
Max iterations500
Total func evals95,403
Num parameters88
Backenddefault.qubit

Provenance / Reproducibility

Entry IDN2_ccpvdz_JW_HEA_v4_casscf_tapered__sha256_17841edecba23ac1
Schema version4.0.0
Created (UTC)2026-07-15T13:31:58.090424+00:00
SHA-256 hash17841edecba23ac15a9e10a9f915754705b1314e5976203749066f2bceb40eed
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 N2 \

--mapping jordan_wigner \

--ansatz-type hea \

--reps 10 \

--orbital-opt casscf \

--multistart 1 \

--max-iter 500 \

--out-dir releases/v4/db