Deep learning with coherent nanophotonic circuits [pdf]
arxiv.org
arxiv.org
I can't help but think it would be really cool to automatically produce a circuit that would output the gradient of the error of the actual NN, so you could optimize that directly.
I've had a short discussion with a professor at my university about the practical efficiency of circuits. It seems like some tasks are better solved with algorithms and others with circuits.
I think that a proper mix between turing machines and circuits will be important in the future of AI.