Adiabatic evolution on a spatial-photonic Ising machine

Combinatorial optimization problems are crucial for widespread applications but remain difficult to solve on a large scale with conventional hardware. Novel optical platforms, known as coherent or photonic Ising machines, are attracting considerable attention as accelerators on optimization tasks formulable as Ising models. Annealing is a well-known technique based on adiabatic evolution for finding optimal solutions in classical and quantum systems made by atoms, electrons, or photons. Although various Ising machines employ annealing in some form, adiabatic computing on optical settings has been only partially investigated. Here, we realize the adiabatic evolution of frustrated Ising models with 100 spins programmed by spatial light modulation. We use holographic and optical control to change the spin couplings adiabatically, and exploit experimental noise to explore the energy landscape. Annealing enhances the convergence to the Ising ground state and allows to find the problem solution with probability close to unity. Our results demonstrate a photonic scheme for combinatorial optimization in analogy with adiabatic quantum algorithms and enforced by optical vector-matrix multiplications and scalable photonic technology.Comment: 9 pages, 4 figure

Design of synchronous reluctance machines with multi-objective optimization algorithms

The design optimization of synchronous reluctance (SyR) machines is considered in this paper by means of a Finite Element Analysis-based multi-objective optimization algorithm (MOOA). The research focuses on the design of the rotor geometry which is the key aspect of SyR machines design. In particular, this digest analyzes the performance of several popular MOOAs and the impact of their settings on the quality of the final design. A procedure to minimize the computational burden of the optimization process is introduced and applied for the first time to a five layer rotor. A rotor prototype has been realized to demonstrate the feasibility of the design procedur