Enabling a Potts machine with phase tristability
Phys. Rev. Applied 24, 034034 – Published 12 September, 2025
DOI: https://doi.org/10.1103/bnzj-5ttt
Abstract
Ising machines efficiently solve binary optimization problems but face scalability limits in nonbinary tasks such as graph coloring due to their bistable dynamics. This work overcomes Ising machine scalability limits by introducing a Potts machine verified with novel experimental data from parametric three-state spins. We realize a three-state spin simulator using a nonlinear electronic oscillator built on the PFD3 (parametric frequency divider-by-three) process, demonstrating phase tristability with three equally probable states separated by 2π/3. Building on this, we construct a three-state Potts machine and determine its ground state using three coupled PFD3 oscillators. Our results show phase tristability onset at 0.76 dBm rf pump power, no dc power requirement, and over 8% conversion efficiency for one PFD3, paving the way for scalable Potts machines with more PFD3 surpassing Ising machines.
