IEEE Nanotechnology Magazine

A High-Performance Digital QUBO Solver for Quantum-Inspired Optimization

Chia‐Ho Ou, Po-Yuan Chu, Tsung-Hsuan Tsai, YiChing Chen, Chih-Yu Chen

Published Dec 30, 2025• 0 citations

Abstract

As Moore’s Law slows, alternative computing paradigms are essential for tackling complex combinatorial optimization problems. This paper introduces DigiQUBO, a high-performance digital Quadratic Unconstrained Binary Optimization (QUBO) solver designed for quantum-inspired optimization. DigiQUBO leverages a advanced Digital Annealing (DA) approach to efficiently solve large-scale QUBO problems, offering a competitive alternative to traditional annealing methods. To evaluate its effectiveness, DigiQUBO is applied to the Traveling Salesman Problem (TSP), a well-known NP-hard problem with applications in logistics, network design, and computational biology. In solving a 40-city Traveling Salesman Problem (TSP), DigiQUBO achieved an average route distance improvement of 13% compared to Simulated Annealing (SA), and a reduction of 37% compared to D-Wave’s LeapHybridSampler, while maintaining comparable runtime to Fujitsu DA3. DigiQUBO significantly enhances solution quality and computational efficiency by integrating two key advanced techniques: two-way one-hot group encoding for improved constraint satisfaction and Bayesian Optimization for automated annealing parameter tuning. Performance comparisons against Simulated Annealing (SA), Fujitsu DA3, and D-Wave’s LeapHybridSampler demonstrate superior results in balancing accuracy and execution time. The results highlight DigiQUBO as a promising digital annealing technology that bridges the gap between classical and quantum optimization, offering a practical and efficient solution in the post-Moore’s Law era.

DOI: 10.1109/mnano.2025.3638505

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