Solving the Hamiltonian Path Problem With a Light-Based Computer

In this paper the authors suggest the use of light for performing useful computations. Namely, they propose a special computational device which uses light rays for solving the Hamiltonian path problem on a directed graph. The device has a graph-like representation and the light is traversing it by following the routes given by the connections between nodes. In each node the rays are uniquely marked so that they can be easily identified. At the destination node they will search only for particular rays that have passed only once through each node. They show that the proposed device can solve small and medium instances of the problem in reasonable time.