Quantum Computing Enabled ab initio Molecular Dynamics Simulations
arXiv:2607.28548
The paper presents a quantum‑classical workflow that combines a chemistry‑inspired LUCJ ansatz with Sample‑based Quantum Diagonalization to perform ab initio molecular dynamics, and benchmarks it against full configuration interaction, showing accurate energies and gradients for both gas‑phase and QM/MM simulations.
Abstract
We demonstrate a quantum-classical workflow for ab initio molecular dynamics (AIMD) in which quantum measurements from a chemistry-inspired LUCJ ansatz are post-processed using Sample-based Quantum Diagonalization (SQD) to recover determinant subspaces and deliver energies and analytical nuclear gradients for dynamics. As an exact benchmark, we use full configuration interaction (FCI) in the STO-3G basis, enabling a direct assessment of the accuracy of SQD. In gas-phase benchmarks, SQD reproduces FCI energies and gradients to within 1 kcal mol of the FCI reference and yields stable AIMD trajectories. In explicit-solvent QM/MM simulations, SQD retains this agreement, matching FCI energy fluctuations and RMS gradient profiles and reproducing solute-solvent structure as quantified by radial distribution functions. Overall, these benchmarks establish LUCJ+SQD as a practical route for integrating current quantum hardware into QM/MM molecular dynamics and provide an early demonstration of condensed-phase QM/MM dynamics driven by a quantum electronic-structure engine.
45 pages, 7 figures. Supporting Information included as an ancillary file