Elucidation of microscopic dynamics of quantum vortex in superfluid helium

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K13503
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Keio University
• Principal Investigator: Nago Yusuke 慶應義塾大学, 理工学部(矢上), 助教 (50623435)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 超流動 / 量子渦 / 量子乱流 / 量子流体 / トポロジー / マイクロ・ナノデバイス

Outline of Final Research Achievements

The purpose of this research is elucidation of motion of quantum vortex which is one of the important factors in a critical behavior of quantum turbulence. We developed nanoelectromechanical systems (NEMS) and vortex generating devices, and performed preliminary experiments of vortex and turbulence generation in superfluid helium, as follows.
1.We fabricated nanoscale mechanical resonators of bridged wire(or beam), made of a carbon nanotube or photo-curing resin, as high sensitivity sensors for quantum vortices. 2.We fabricated orifice plate oscillators for generation of quantum vortex rings, and observed dissipation of oscillation due to vortex generation in superfluid helium.

Free Research Field

低温物性

Academic Significance and Societal Importance of the Research Achievements

超流動ヘリウム中の量子渦・量子乱流はシンプルな構造の超流動流の渦で構成されるため、その本質の理解は、古典流体やプラズマ中の渦・乱流現象や宇宙における位相欠陥など広範な分野の物理の理解に密接に関わる。量子乱流に関わる量子渦の微視的な運動状態の解明には、ナノサイズの微小なセンサーが必須であり、本研究によって量子渦のナノセンシング確立に進捗が得られたことは意義が大きい。また、渦の生成・制御が実現できる渦環生成装置の開発は、今後どのような渦がどのように振舞うかを直接観測できる実験系の実現に向けて大きく貢献したと言える。