  Spin Glasses (SG) are paradigmatic models for physical, computer science,
biological and social systems. The problem of studying the dynamics for SG
models is NP hard, i.e., no algorithm solves it in polynomial time. Here we
implement the optical simulation of a SG, exploiting the N segments of a
wavefront shaping device to play the role of the spin variables, combining the
interference at downstream of a scattering material to implement the random
couplings between the spins (the J ij matrix) and measuring the light intensity
on a number P of targets to retrieve the energy of the system. By implementing
a plain Metropolis algorithm, we are able to simulate the spin model dynamics,
while the degree of complexity of the potential energy landscape and the region
of phase diagram explored is user-defined acting on the ratio the P/N = \alpha.
We study experimentally, numerically and analytically this peculiar system
displaying a paramagnetic, a ferromagnetic and a SG phase, and we demonstrate
that the transition temperature T g to the glassy phase from the paramagnetic
phase grows with \alpha. With respect to standard in silico approach, in the
optical SG interaction terms are realized simultaneously when the independent
light rays interferes at the target screen, enabling inherently parallel
measurements of the energy, rather than computations scaling with N as in
purely in silico simulations.
