Analog quantum computing (AQC) by revisiting the underlying physics

摘要

It has been proven that universal quantum computers based on qubits and classical analog networks both have superTuring capabilities. It is a grand challenge to computer science to prove that the combination of the two, in analog (continuous variable) quantum computing, offers supersuperTuring capability, the best we can achieve. Computing with continuous spins is now the most promising path AQC. Two papers at SPIE2014 described unbreakable quantum codes using continuous spins beyond what traditional qubits allow. To make this real, we must first develop a realistic ability to model and predict the behavior of networks of spin gates which act in part as polarizers. Last year I proposed a triphoton experiment, where three entangled photons go to linear polarizers set to angles θ_a, θ_b and θ_c. Assuming a "collapse of the wave function" yields predictions for the coincidence detection rate, R_3/R_0(θ_a,θ_b,θ_c) significantly different from the prediction of a new family of models based on classical Markov Random Fields (MRF) across space time, even though both yield the same correct prediction in the two-photon case. We cannot expect to predict systems of 100 entangled photons correctly if we cannot even predict three yet. Yanhua Shih is currently performing this experiment, as a first step to demonstrating a new technology to produce 100 entangled photons (collaborating with Scully) and understanding larger systems. I have also developed continuous-time versions of the MRF models and of "collapse of the wave function", so as to eliminate the need to assume metaphysical observers in general.