2026-09-25 東京大学素粒子物理国際研究センター,東京科学大学
図1：実験に用いた超伝導マイクロ波共振器
（a）共通フィードラインに結合した4つの1/4波長共振器。（b）共振器の接地端に設けたテーパー部と細い狭窄部（ネック）の拡大像。右上は狭窄部近傍のさらに拡大した像。ネックで電流密度を高めることで、渦糸侵入に対する感度を向上させています。
＜関連情報＞
- https://www.icepp.s.u-tokyo.ac.jp/information/20260925.html
- https://journals.aps.org/prl/abstract/10.1103/4zw3-hm6t
共平面超伝導共振器における個々の渦の侵入の観測 Observation of Individual Vortex Penetration in a Coplanar Superconducting Resonator
Kirill Shulga, Shunsuke Nishimura, Pavel A. Volkov, Miu Hirano, Toshiaki Inada, Ryota Hasegawa, Takeyuki Tsuji, Takayuki Iwasaki, Mutsuko Hatano et al.
Physical Review Letters Published: 10 September, 2026
DOI: https://doi.org/10.1103/4zw3-hm6t
Abstract
We demonstrate the microwave signatures of individual Abrikosov-vortex penetration events in superconducting microwave resonators. /4 resonators with a narrowed region near the grounded end acting as a vortex trap were fabricated and studied using microwave transmission spectroscopy at millikelvin temperatures. Sharp stepwise drops in resonance frequency are detected as a function of increasing external magnetic field, attributed to the entry of individual Abrikosov vortices in the narrow region. This interpretation is confirmed by nitrogen-vacancy center magnetometry, revealing discrete vortex entry events on increasing field and the absence of such drops in a device with a wider narrowed region. Our results establish a method to investigate and manipulate the states of Abrikosov vortices with microwaves access and readout vortex configurations using magnetic-field sweeps and microwave drive.
