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Building Quantum Computers With Photons

photonic chip, illustration

The two-qubit processor's developers say it shows a practical way to implement a large-scale photonic quantum processor.

Credit: Xiaogang Qiang / University of Bristol

Researchers at the National University of Defense Technology in China have built a photonic quantum processor, which generates and manipulates two photonically encoded quantum bits (qubits) for universal two-qubit quantum computing.

The photons are encoded via thermo-optical phase shifters controlled by electrical voltages. The National University's Xiaogang Qiang says, "Different settings of the phase shifters control the photon's transmission behaviors in the interferometers, enabling different qubit-state encoding and different quantum operations."

Upscaling the system and packing sufficient phase shifters, beam splitters, and other optical components onto the chip to produce a practical solution are significant challenges. However, Xiaogang says silicon photonics has demonstrated the capacity for bundling many devices tightly and inducing them to operate with high precision, "and thus it in fact is the practical way to implement the ultimate large-scale photonic quantum processor."

From IEEE Spectrum
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