近日，美国国家标准与技术研究院的Dietrich Leibfried及其研究团队取得一项新进展。经过不懈努力，他们实现捕获离子机械振荡器的相干耦合与无损测量。相关研究成果已于2024年7月29日在国际知名学术期刊《自然—物理学》上发表。
该研究团队成功证明了在捕获离子晶体的频谱分离的谐波运动模式之间，单运动量子的相干交换现象。他们通过施加具有适当空间变化的振荡电位，精确控制了耦合的时间、强度和相位。由于耦合速率远大于退相干速率，该研究成功展示了高保真度的量子态转移和分束操作、运动模式纠缠以及Hong–Ou–Mandel型干涉。
此外，研究人员还利用运动耦合技术，实现了对捕获离子运动状态的重复非破坏性投影测量。这一研究成果显著增强了捕获离子运动在连续变量量子计算和纠错领域的适用性，并为提升运动冷却和运动介导的纠缠相互作用的性能提供了新的机会。
据悉，精确的量子控制和测量几个谐振子，如腔内电磁场或机械运动的模式，是将它们用作量子平台的关键。捕获离子的运动模式可以单独控制，并具有良好的相干性。然而，实现高保真双模操作和无损测量运动状态一直是一个挑战。
附：英文原文
Title: Coherent coupling and non-destructive measurement of trapped-ion mechanical oscillators
Author: Hou, Pan-Yu, Wu, Jenny J., Erickson, Stephen D., Cole, Daniel C., Zarantonello, Giorgio, Brandt, Adam D., Geller, Shawn, Kwiatkowski, Alex, Glancy, Scott, Knill, Emanuel, Wilson, Andrew C., Slichter, Daniel H., Leibfried, Dietrich
Issue&Volume: 2024-07-29
Abstract: Precise quantum control and measurement of several harmonic oscillators, such as the modes of the electromagnetic field in a cavity or of mechanical motion, are key for their use as quantum platforms. The motional modes of trapped ions can be individually controlled and have good coherence properties. However, achieving high-fidelity two-mode operations and non-destructive measurements of the motional state has been challenging. Here we demonstrate the coherent exchange of single motional quanta between spectrally separated harmonic motional modes of a trapped-ion crystal. The timing, strength, and phase of the coupling are controlled through an oscillating electric potential with suitable spatial variation. Coupling rates that are much larger than decoherence rates enable demonstrations of high-fidelity quantum state transfer and beam-splitter operations, entanglement of motional modes, and Hong–Ou–Mandel-type interference. Additionally, we use the motional coupling to enable repeated non-destructive projective measurement of a trapped-ion motional state. Our work enhances the suitability of trapped-ion motion for continuous-variable quantum computing and error correction and may provide opportunities to improve the performance of motional cooling and motion-mediated entangling interactions.
DOI: 10.1038/s41567-024-02585-y
Source: https://www.nature.com/articles/s41567-024-02585-y