Enhancing Oscillator-Based Ising Machine Models with Amplitude Dynamics and Polynomial Interactions

Abstract: We present an oscillator model with both phase and amplitude dynamics for oscillator-based Ising machines that addresses combinatorial optimization problems with polynomial cost functions of arbitrary order. Our approach addresses fundamental limitations of previous oscillator-based Ising machines through a mathematically rigorous formulation with a well-defined energy function and corresponding dynamics. The model demonstrates monotonic energy decrease and reliable convergence to low-energy states. Empirical evaluations on 3-SAT problems show significant performance improvements over existing phase-amplitude models. Additionally, we propose a flexible, generalizable framework for designing higher-order oscillator interactions, from which we derive a practical method for oscillator binarization without compromising performance. This work strengthens both the theoretical foundation and practical applicability of oscillator-based Ising machines for complex optimization problems.