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由于交流连贯量子相位滑动效应而导致的量化电流阶段
Rais S Shaikhaidarov1,2, Kyung Ho Kim1, Jacob W Dunstan1
1Royal Holloway, University of London, Egham, UK.
Nature
|July 25, 2022
概括
研究人员直接观察了超导纳米线中的双Shapiro步骤,证明了量子化的电流步骤. 这一突破对于当前的量子标准至关重要,
科学领域:
- 凝聚物质物理学
- 量子计量学
- 超导性
背景情况:
- 作为量化电压步骤 (沙皮罗步骤) 观察到的AC约瑟夫森效应是量子力学和电压标准的基础.
- 双重效应,交流连贯量子相位滑动 (CQPS),涉及磁流道化,预计将表现为量子化电流步骤.
- CQPS对于未来的现有标准和量子计量三角形的关闭至关重要,但对现有步骤的直接观察是难以捉摸的.
研究的目的:
- 在超导纳米线中直接观察双Shapiro步骤或量子化电流步骤.
- 克服材料和电路工程的局限性,这些局限性以前阻止了这些现有步骤的实验实现.
- 推动量子电流标准的发展.
主要方法:
- 使用NbN材料制造超导纳米线装置.
- 将纳米线集成到诱导环境中以抑制扩展效应.
- 在微波辐射下测试电流步骤,直至26GHz.
主要成果:
- 在超导纳米线中直接观察利的量子化电流步骤,类似于双 Shapiro 步骤.
- 观察到的步骤可以清除到26GHz的频率,测量的电流值为8.3nA.
- 观察到的现象归因于交流连贯量子相位滑动 (CQPS) 效应.
结论:
- 这项研究成功地证明了在超导纳米线中直接观察量子化电流的步骤.
- 这一成就克服了长期以来在超导体中实现平流阶段的挑战,此前由于材料和电路的限制而受到阻碍.
- 这些发现为量子电流标准的实际应用铺平了道路, 并完成了量子计量三角形.
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