Large-Scale Photonic Ising Machine by Spatial Light Modulation

Abstract

Quantum and classical physics can be used for mathematical computations that\nare hard to tackle by conventional electronics. Very recently, optical Ising\nmachines have been demonstrated for computing the minima of spin Hamiltonians,\npaving the way to new ultra-fast hardware for machine learning. However, the\nproposed systems are either tricky to scale or involve a limited number of\nspins. We design and experimentally demonstrate a large-scale optical Ising\nmachine based on a simple setup with a spatial light modulator. By encoding the\nspin variables in a binary phase modulation of the field, we show that light\npropagation can be tailored to minimize an Ising Hamiltonian with spin\ncouplings set by input amplitude modulation and a feedback scheme. We realize\nconfigurations with thousands of spins that settle in the ground state in a\nlow-temperature ferromagnetic-like phase with all-to-all and tunable pairwise\ninteractions. Our results open the route to classical and quantum photonic\nIsing machines that exploit light spatial degrees of freedom for parallel\nprocessing of a vast number of spins with programmable couplings.\n