美国哈佛大学约翰·A·保尔森工程与应用科学学院Marko Loncar团队实现了利用光对超导量子比特进行相干控制。2025年4月2日出版的《自然—物理学》杂志发表了这项成果。

量子通信技术需要一个与能够分布纠缠态的低损耗和低噪声通信信道连接的量子处理器网络。在低温环境中工作的超导微波量子比特已成为量子处理器节点的有前景的候选者。然而，扩展这些系统是具有挑战性的，因为它们需要具有高热负载的笨重微波组件，这些组件可能会迅速压倒稀释冰箱的冷却能力。

然而，电信频率光信号可以以显著更小的形状因子制造，以避免由于其高载波频率和在石英光纤中的传播而导致的高信号损耗、噪声敏感性和热负荷所带来的挑战。因此，通过光学和微波频率之间的相干链路传递信息对于利用光学在超导微波量子位方面的优势至关重要，同时也使超导处理器能够与低损耗光学互连连接。

研究组演示了超导量子比特的相干光学控制。通过开发一种微波-光学量子换能器来实现这一目标，该换能器在低附加微波噪声下以高达1.18%的转换效率运行，他们还演示了超导子比特中的光学驱动拉比振荡。

附：英文原文

Title: Coherent control of a superconducting qubit using light

Author: Warner, Hana K., Holzgrafe, Jeffrey, Yankelevich, Beatriz, Barton, David, Poletto, Stefano, Xin, C. J., Sinclair, Neil, Zhu, Di, Sete, Eyob, Langley, Brandon, Batson, Emma, Colangelo, Marco, Shams-Ansari, Amirhassan, Joe, Graham, Berggren, Karl K., Jiang, Liang, Reagor, Matthew J., Lonar, Marko

Issue&Volume: 2025-04-02

Abstract: Quantum communications technologies require a network of quantum processors connected with low-loss and low-noise communication channels capable of distributing entangled states. Superconducting microwave qubits operating in cryogenic environments have emerged as promising candidates for quantum processor nodes. However, scaling these systems is challenging because they require bulky microwave components with high thermal loads that can quickly overwhelm the cooling power of a dilution refrigerator. Telecommunication frequency optical signals, however, can be fabricated in significantly smaller form factors to avoid challenges caused by high signal loss, noise sensitivity and thermal loads due to their high carrier frequency and propagation in silica optical fibres. Transduction of information by means of coherent links between optical and microwave frequencies is therefore critical to leverage the advantages of optics for superconducting microwave qubits, while also enabling superconducting processors to be linked with low-loss optical interconnects. Here, we demonstrate coherent optical control of a superconducting qubit. We achieve this by developing a microwave–optical quantum transducer that operates with up to 1.18% conversion efficiency with low added microwave noise, and we demonstrate optically driven Rabi oscillations in a superconducting qubit.

DOI: 10.1038/s41567-025-02812-0

Source: https://www.nature.com/articles/s41567-025-02812-0