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科学网|《自然》（20201022出版）一周论文导读( 二 )


光通过多通道上的直接光纤耦合有效地传输到低温环境下的捕集芯片上 ， 从而消除了将光束对准真空系统和低温器的需要 ， 并对振动和波束指向漂移提供了鲁棒性 。 这使得我们可以对离子运动进行基态激光冷却 ， 并实现产生精确性大于99.3(2)%的双离子纠缠态的门 。
这项工作演示了在敏感量子逻辑中可以降低噪音和漂移的硬件 ， 同时为高保真量子处理器的实际并行化提供了途径 。 类似的装置也可能在原子和离子量子传感和计时中得到应用 。
▲ Abstract
Practical and useful quantum information processing requires substantial improvements with respect to current systems, both in the error rates of basic operations and in scale. Here we use 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 allows us to perform ground-state laser cooling of ion motion and to implement gates generating two-ion entangled states with fidelities greater than 99.3(2) 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. Similar devices may also find applications in atom- and ion-based quantum sensing and timekeeping.
Integrated multi-wavelength control of an ion qubit
离子量子位的集成多波长控制
▲ 作者：R. J. Niffenegger, J. Stuart, C. Sorace-Agaskar, D. Kharas, S. Bramhavar, C. D. Bruzewicz, W. Loh, R. T. Maxson, R. McConnell, D. Reens, G. N. West, J. M. Sage & J. Chiaverini
▲ 链接：
▲ 摘要
原子系统控制技术的单片集成是发展量子计算机和便携式量子传感器的一条很有前途的发展道路 。 捕获的原子离子构成了高保真量子信息处理器和高精度光学钟的基础 。
然而 ， 目前的实现依赖于自由空间光学来进行离子控制 ， 这限制了它们的可移植性和可伸缩性 。
在此 ， 我们展示了一个使用集成波导和光栅耦合器的表面电极离子阱芯片 ， 它可以提供电离、冷却、相干操作、量子态制备和锶量子位元检测所需的所有波长的光 。
从紫到红外的激光通过光纤阵列耦合到芯片上 ， 创造出固有的稳定光路 ， 我们用它来证明量子位相干性对平台振动的弹性 。
这一CMOS兼容的集成光子表面阱制造、强大的封装和增强的量子比特相干性的演示 ， 是便携式捕获离子量子传感器和时钟发展的关键进展 ， 提供了一种在量子信息处理系统中对大量离子进行完全独立控制的方法 。
▲ Abstract
Monolithic integration of control technologies for atomic systems is a promising route to the development of quantum computers and portable quantum sensors. Trapped atomic ions form the basis of high-fidelity quantum information processors and high-accuracy optical clocks. However, current implementations rely on free-space optics for ion control, which limits their portability and scalability. Here we demonstrate a surface-electrode ion-trap chip using integrated waveguides and grating couplers, which delivers all the wavelengths of light required for ionization, cooling, coherent operations and quantum state preparation and detection ofqubits. Laser light from violet to infrared is coupled onto the chip via an optical-fibre array, creating an inherently stable optical path, which we use to demonstrate qubit coherence that is resilient to platform vibrations. This demonstration of CMOS-compatible integrated photonic surface-trap fabrication, robust packaging and enhanced qubit coherence is a key advance in the development of portable trapped-ion quantum sensors and clocks, providing a way towards the complete, individual control of larger numbers of ions in quantum information processing systems.材料科学Material Science


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