Investigation on Oscillator-Based Ising Machines

Abstract

Moore’s law is slowing down and, as traditional von Neumann computers face challenges in efficiently handling increasingly important issues in a modern information society, there is a growing desire to find alternative computing and device technologies. Ising machines are non-von Neumann computing systems designed to solve combinatorial optimization problems. To explore their efficient implementation, Ising machines have been developed using a variety of physical principles such as optics, electronics, and quantum mechanics. Among them, oscillator-based Ising machines (OIMs) utilize synchronization dynamics of network-coupled spontaneous nonlinear oscillators. In these OIMs, phases of the oscillators undergo binarization through second-harmonic injection signals, which effectively transform the broad class of network-coupled oscillator systems into Ising machines. This makes their implementation versatile across a wide variety of physical phenomena. In this Chapter, we discuss the fundamentals and working mechanisms of the OIMs. We also numerically investigate the relationship between their performance and their properties, including some unexplored effects regarding driving stochastic process and higher harmonics, which have not been addressed in the existing literature.