A Reality Check on Quantum Optimisation: Evidence from an Industrial Case Study
For industrial practitioners considering quantum optimization, this provides a realistic assessment of current capabilities and limitations, showing incremental progress rather than breakthrough.
The paper evaluates quantum, quantum-inspired, and classical methods on an industrial Job-Shop Scheduling Problem, finding that hardware-software co-design is crucial and that current quantum approaches show potential for early proof-of-concept but not yet practical advantage over classical solvers.
Quantum Processing Units promise speed-ups for selected computational problems, including combinatorial optimisation, but their industrial utility remains an open challenge. We study an industrial variant of the Job-Shop Scheduling Problem using quantum, quantum-inspired, and classical methods across three platforms: IBM Quantum, the D-Wave Quantum Annealer, and the Fujitsu Digital Annealer. By tailoring formulations to hardware-specific constraints, we show that hardware-software co-design is essential for solution quality and scalability. We benchmark all approaches against an exact classical solver and a MILP formulation, evaluating runtime, solution quality, and scalability. Our results indicate that quantum and quantum-inspired optimisation can support industrial solver selection, integration in classical workflows, modelling decisions, and early proof-of-concept development, while suggesting a potential path towards improved approximations for industrial scheduling.