Phy.org October 22, 2020
The fundamental qualities of individual trapped-ion qubits are promising for long-term systems, but the optics involved in their precise control are a barrier to scaling. Researchers in Switzerland used scalable optics co-fabricated with a surface-electrode ion trap to achieve high-fidelity multi-ion quantum logic gates, which are often the limiting elements in building up the precise, large-scale entanglement that is essential to quantum computation. Light is efficiently delivered to a trap chip in a cryogenic environment via direct fibre coupling on multiple channels, eliminating the need for beam alignment into vacuum systems and cryostats and lending robustness to vibrations and beam-pointing drifts. This allowed implementing gates generating two-ion entangled states with fidelities greater than 99.3 per cent. This work demonstrates hardware that reduces noise and drifts in sensitive quantum logic, and simultaneously offers a route to practical parallelization for high-fidelity quantum processors…read more. TECHNICAL ARTICLE
An ion trap with integrated waveguides. The laser light (red) for controlling the two trapped ions (blue) is delivered to the ion traps inside the chip. Credit: Chiara Decaroli / ETH Zurich