Graver Bases via Quantum Annealing with Application to Non-Linear Integer Programs

We propose a novel hybrid quantum-classical approach to calculate Graver bases, which have the potential to solve a variety of hard linear and non-linear integer programs, as they form a test set (optimality certificate) with very appealing properties. The calculation of Graver bases is exponentially hard (in general) on classical computers, so they not used for solving practical problems on commercial solvers. With a quantum annealer, however, it may be a viable approach to use them. We test two hybrid quantum-classical algorithms (on D-Wave)--one for computing Graver basis and a second for optimizing non-linear integer programs that utilize Graver bases--to understand the strengths and limitations of the practical quantum annealers available today. Our experiments suggest that with a modest increase in coupler precision--along with near-term improvements in the number of qubits and connectivity (density of hardware graph) that are expected--the ability to outperform classical best-in-class algorithms is within reach, with respect to non-linear integer optimization.