Boson sampling is a problem strongly believed to be intractable for classical computers, but can be naturally solved on a specialized photonic quantum simulator. Here, we implement the first time-bin-encoded boson sampling using a highly indistinguishable (∼94%) single-photon source based on a single quantum-dot-micropillar device. The protocol requires only one single-photon source, two detectors, and a loop-based interferometer for an arbitrary number of photons. The single-photon pulse train is time-bin encoded and deterministically injected into an electrically programmable multimode network. The observed three- and four-photon boson sampling rates are 18.8 and 0.2 Hz, respectively, which are more than 100 times faster than previous experiments based on parametric down-conversion.

This paper presents a cross-coupled control approach to the tracking control of parallel manipulators in a synchronous manner. Based on the synchronization goal, the position synchronization error is investigated by considering motion synchronization between each actuator joint and its adjacent ones. A decentralized trajectory tracking controller is then developed with feedback of both position and synchronization errors, formed with a combination of feedforward, feedback and a saturation control. It is proven that this tracking controller can asymptotically stabilize both position and synchronization errors of the system. The proposed controller does not require the explicit use of the system dynamic model. Experiments performed on a 3-DOF parallel manipulator demonstrate improved performance with the proposed synchronous control design.

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