So very cool... what a crazy device! Ok. Groovy. I got that. But... how do they know the final phase state? I mean, they are looking for the "lowest" and "highest" values, but these change over time as the signals pass around the loop again and again and again. So how do they know what the "lowest" energy state is? Does it reach a state where subsequent loops don't drop the voltage any further? Or is there a lowest possible voltage the system can support, and when it hits that level it's called 'done' and that's the final state? I love the detail of how the thing works, and the beam splitting and reference pulses, and how the FPGA is the thing actually making the calculation... but how do they know when it is done, or the problem is solved? What am I missing? The result is assessed in terms of the problem’s total energy, with the lowest energy state as the optimal solution.
We repeat the whole process for each OPO pulse in the loop, and it can take tens to hundreds of trips around the loop for all the pulses to achieve their final phase states.
Yeah, that optical table experimental setup looks... really accessible (hundreds of meters of fiber optics). butforreal :( I'll never forget, there was this undergrad chick presenting to our mixed grad-undergrad class, and she computationally modeled a 2D Ising model for a few cases, like adiabatic cooling, or stochastic heating, and other situations resembling paleomagnetization, etc., but yeah, I remember it being incredible. It blew my shitty little grad student project out of the water. There are some absolutely brilliant people out there, just lurking. Maybe you.
I got to the point where he said "that's a mouthful" and then I stopped understanding what is happening. What is happening in the optic Fibre spool? If I understood correctly, it is like doing computations but using light to do the calculation. I just don't get how you translate a problem like the traveling salesman to these pulses and come up. With an answer.