2020 Fiscal Year Final Research Report

Search for dark matter axions using superconducting junctions

Research Project

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Project/Area Number	18H01243
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
Research Institution	Nagoya University
Principal Investigator	Kashiwaya Satoshi 名古屋大学, 工学研究科, 教授 (40356770)
Co-Investigator(Kenkyū-buntansha)	山森弘毅国立研究開発法人産業技術総合研究所, エレクトロニクス・製造領域, 研究グループ長 (00358293) 中竜大東邦大学, 理学部, 講師 (00608888) 田仲由喜夫名古屋大学, 工学研究科, 教授 (40212039) 北嶋直弥東北大学, 学際科学フロンティア研究所, 助教 (50737955)
Project Period (FY)	2018-04-01 – 2021-03-31
Keywords	暗黒物質アクシオン / ジョセフソン接合 / トポロジカル量子現象
Outline of Final Research Achievements	We aim to establish the basic concept of the interaction between Josephson junctions and axion, and to establish a method for searching for axion by using only laboratory-based devices. Initially, the experiment was carried out by detecting the signal related to the axion from the conductance of the Josephson junctions, but the structure originated by the axion was not observed. Therefore, we proceeded with theoretical analysis and experiments based on the resonantly generated magnetic field from the rf current. It was shown that the generated magnetic field resonantly increases by matching the rf frequency and the axion frequency, and can be measured by high-sensitivity magnetic field detection such as SQUID. Currently, we are developing a device with a unique structure that combines SQUID and Josephson junctions, and are now proceeding with measurements.
Free Research Field	低温物理
Academic Significance and Societal Importance of the Research Achievements	アクシオン検出は世界的に多くの研究がおこなわれているが、従来行われてきた巨大施設を用いた検出方法とは異なる事件室系の装置のみを用いた、共鳴効果に基づく新しい検出方法を提案し、実際にジョセフソン素子とSQUIDを用いた観測を進めている。現状ではまだ観測には至っていないが、今後研究を進めることで、実験室系の装置のみでのアクシオン検出を実現することを目指している。アクシオンが実際に観測できれば、素粒子宇宙物理分野に多大な波及効果のある有意義な研究となる。