Large-scale Ising Emulation with Four-Body Interaction and All-to-All Connection

We propose and demonstrate a nonlinear optics approach to emulate Ising machines containing up to a million spins and with tailored two and four-body interactions with all-to-all connections. It uses a spatial light modulator to encode and control the spins in the form of the binary phase values of wavelets in coherent laser beams, and emulates the high-order interaction with frequency conversion in a nonlinear crystal at the Fourier plane. By adaptive feedback control, the system can be evolved into effective spin configurations that well approximate the ground states of Ising Hamiltonians with all-to-all connected many-body interactions. Our technique could serve as a new tool to probe complex, many-body physics and give rise to exciting applications in big data optimization, computing, and analytics.