Technical articles on quantum algorithm benchmarking, VQE methodology, and reproducible quantum chemistry evaluation.
We added water to the QEncode benchmark suite. Here's what it takes to simulate H₂O with a [4,4] active space — 8 qubits, 105 Pauli terms, and what the VQE results reveal about UCCSD's limits at this scale.
The leaderboard shows two thresholds: a 1.6 mHa chemical accuracy line and a 10 mHa certification threshold. Here's why they're different, what the colored bars measure, and how to read H₂O's red bars alongside H₂'s green ones.
Before you run a single VQE circuit you have to pick a qubit encoding. We compared JW, parity, and Bravyi-Kitaev across five molecules with real benchmark data — circuit depth, gate count, and accuracy all measured under identical conditions.
We ran both ansatz families across five molecules at three encodings and measured energy gap, circuit depth, and two-qubit gate count. Here's what the numbers say — and why the winner depends on what you're optimizing for.
Most published VQE results can't be reproduced. The reasons are technical but fixable: underdocumented ansatz construction, hardware-specific transpilation, and no standard error metric. QEncode Suite v2 addresses all three.
