Demonstration of Parallel Multi-QPU Execution for Fragment-Based Quantum Chemistry Using On-Premises Hardware
Abstract
Fragment molecular orbital (FMO) quantum chemistry offers a natural route to parallel quantum computing: large molecular calculations can be decomposed into smaller quantum subproblems that can, in principle, run concurrently. Their practical benefit on real quantum hardware, however, has remained unclear. We demonstrate parallel FMO calculations on three room-temperature diamond-based 'Quoll' quantum computers installed on-site at the Oak Ridge Leadership Computing Facility. Helium clusters (Hen, n=2,4,8,10,14) served as a testbed for total energy calculations using the Quantum Wave Function Sampler (QWFS), a selected configuration interaction (SCI) approach. We compare two execution modes: synchronous shot-parallel execution, in which quantum processors jointly sample QWFS circuits and combine their SPAM-corrected counts into a single probability distribution; and asynchronous fragment-parallel execution, in which processors independently evaluate FMO fragments using device-specific optimized circuits. Both modes increase quantum sampling throughput without systematic loss of accuracy. The three-QPU shot-parallel workflow reaches a parallel efficiency of 93.60%, while the fragment-parallel workflow achieves a measured efficiency of 75.01%, increasing to 95.17% when excluding the non-useful idle time associated with non-interruptible submitted jobs. In both cases, the assembled FMO-QWFS energies remain chemically accurate compared to the classical ideal. These results provide a proof-of-concept demonstration that parallel quantum execution can improve the practical throughput of quantum chemistry workflows on prototype hardware, motivating the development of future HPC environments with many fault-tolerant quantum processors operating as a distributed resource for molecular and materials simulation.
Related
- vibe-queue: provenance-aware job execution for computational chemistry across workstations and clusters
- Quantum-Classical Effective Fragment Potential Embedding for Condensed-Phase Quantum Chemistry
- A resource-efficient structure-based workflow for fragment progression enables parallel hit discovery and validation of functionally diverse modulators of NCS-1 protein–protein interactions
- From Execution to Discovery : Physical Verification as the Key Gap in AI Agents for Science
- ETALON: Verified Execution and Persistent Research Memory for Agentic Computer-Aided Drug Design
BibTeX
@misc{herrmann2026demonstration,
title = {{Demonstration of Parallel Multi-QPU Execution for Fragment-Based Quantum Chemistry Using On-Premises Hardware}},
author = {Nils Herrmann and Mariam Akhtar and Luke W. Bertels and Leigh Cameron and Raymond Chan and Lei Cheng and Daniel Claudino and Mark de Burgh and Simon Gemmell and Rugang Geng and Geoff Gillett and Travis Humble and Stephan Irle and John P. McMahon and Christian Ortiz and Florian Preis and Andreas Sawadsky and Bianca Sawyer and Reuben Singer and Sai Meghana Tunikipati and Cameron Walters and Lachlan Whichello and Adam Zegelin and Marcus W. Doherty},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.07702},
eprint = {2610.07702},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.07702},
}
RIS
TY - UNPB
TI - Demonstration of Parallel Multi-QPU Execution for Fragment-Based Quantum Chemistry Using On-Premises Hardware
AU - Nils Herrmann
AU - Mariam Akhtar
AU - Luke W. Bertels
AU - Leigh Cameron
AU - Raymond Chan
AU - Lei Cheng
AU - Daniel Claudino
AU - Mark de Burgh
AU - Simon Gemmell
AU - Rugang Geng
AU - Geoff Gillett
AU - Travis Humble
AU - Stephan Irle
AU - John P. McMahon
AU - Christian Ortiz
AU - Florian Preis
AU - Andreas Sawadsky
AU - Bianca Sawyer
AU - Reuben Singer
AU - Sai Meghana Tunikipati
AU - Cameron Walters
AU - Lachlan Whichello
AU - Adam Zegelin
AU - Marcus W. Doherty
PY - 2026
DA - 2026/10/06
PB - arXiv
DO - 10.48550/arxiv.2610.07702
UR - https://arxiv.org/abs/2610.07702
AB - Fragment molecular orbital (FMO) quantum chemistry offers a natural route to parallel quantum computing: large molecular calculations can be decomposed into smaller quantum subproblems that can, in principle, run concurrently. Their practical benefit on real quantum hardware, however, has remained unclear. We demonstrate parallel FMO calculations on three room-temperature diamond-based 'Quoll' quantum computers installed on-site at the Oak Ridge Leadership Computing Facility. Helium clusters (He_n, n=2,4,8,10,14) served as a testbed for total energy calculations using the Quantum Wave Function Sampler (QWFS), a selected configuration interaction (SCI) approach. We compare two execution modes: synchronous shot-parallel execution, in which quantum processors jointly sample QWFS circuits and combine their SPAM-corrected counts into a single probability distribution; and asynchronous fragment-parallel execution, in which processors independently evaluate FMO fragments using device-specific optimized circuits. Both modes increase quantum sampling throughput without systematic loss of accuracy. The three-QPU shot-parallel workflow reaches a parallel efficiency of 93.60%, while the fragment-parallel workflow achieves a measured efficiency of 75.01%, increasing to 95.17% when excluding the non-useful idle time associated with non-interruptible submitted jobs. In both cases, the assembled FMO-QWFS energies remain chemically accurate compared to the classical ideal. These results provide a proof-of-concept demonstration that parallel quantum execution can improve the practical throughput of quantum chemistry workflows on prototype hardware, motivating the development of future HPC environments with many fault-tolerant quantum processors operating as a distributed resource for molecular and materials simulation.
ER -