Variational quantum methods improve copper site chemical simulations greatly
VQE Validation on the Mononuclear T1 (Blue-Copper) Site: A Stepping Stone to the Multi-Copper Laccase Cluster
Emerging Technologies
Summary
Simulating molecules with many electrons is very hard for regular computers. The authors tested a quantum computing approach called VQE on a specific copper atom site in a molecule, using an emulator (a classical simulation of a quantum computer). Their tailored method greatly reduced error compared to other approaches and approached nearly exact results. This work lays the foundation for running such chemistry simulations on real quantum hardware in the future.
What this means in practice
- •For quantum algorithm developers: Benchmark and improve VQE algorithms for chemical systems using problem-specific operator pools demonstrated on simulated copper site molecules.
- •For quantum hardware engineers: Use emulator results as baselines to validate and guide upcoming real quantum hardware runs for molecular simulations.
Authors
Lucia Malickova
Abstract
Validating variational quantum eigensolver (VQE) pipelines on realistic chemical systems is a critical stepping stone toward tackling classically intractable molecules. In this work, we report emulator-based validation of the VQE workflow proposed for the copper active site, executed on the LRZ Eviden Qaptiva emulator. A problem-tailored ADAPT-VQE with a full singles-doubles-triples (S+D+T) pool removes over 99% of the correlation error, reaching a stable plateau at 4.03 mEh relative to exact diagonalisation (148 selected operators). This establishes a >40x improvement over the hardware-efficient ansatz (HEA). Finally, we frame these emulator results as a robust baseline for upcoming physical quantum hardware runs on Euro-Q-Exa.