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Novel Quantum Phenomena in 2D Helium with Aspects of Quantum Phase Transition

Research Project

Project/Area Number 20H00132
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Review Section Medium-sized Section 13:Condensed matter physics and related fields
Research InstitutionKeio University

Principal Investigator

Shirahama Keiya  慶應義塾大学, 理工学部(矢上), 教授 (70251486)

Co-Investigator(Kenkyū-buntansha) 永合 祐輔  慶應義塾大学, 理工学部(矢上), 助教 (50623435)
Project Period (FY) 2020-04-01 – 2023-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥45,760,000 (Direct Cost: ¥35,200,000、Indirect Cost: ¥10,560,000)
Fiscal Year 2022: ¥7,020,000 (Direct Cost: ¥5,400,000、Indirect Cost: ¥1,620,000)
Fiscal Year 2021: ¥17,550,000 (Direct Cost: ¥13,500,000、Indirect Cost: ¥4,050,000)
Fiscal Year 2020: ¥21,190,000 (Direct Cost: ¥16,300,000、Indirect Cost: ¥4,890,000)
Keywords物性物理 / 低温物理 / 量子流体固体 / 超流動 / 量子相転移 / ヘリウム / 非平衡 / 量子液体固体 / フォノン / 誘電率 / 窒化ホウ素
Outline of Research at the Start

ヘリウム薄膜は「2次元強相関量子多体系」として、トポロジカル超流動、量子液晶、非平衡などの新現象を示しうる。申請者は2次元ヘリウムの性質が「励起にエネルギーギャップをもつ局在固体」と「超流動」間の「量子相転移」という見方―量子相転移描像―で統一的に理解できることを提案している。
本研究ではこの量子相転移描像に基づき、2次元ヘリウムに期待される新奇量子現象を開拓する。具体的には、(1)フォノン照射による非平衡超流動状態の実現、(2)純2次元トポロジカル超流動ヘリウム3の探索、(3)ヘリウム4薄膜における固体と超流動の共存の検証、という3つの新奇量子凝縮相・量子現象の解明に取り組む。

Outline of Final Research Achievements

Thin He films on solid surfaces are 2D strongly correlated systems which show a variety of novel physical phenomena. We have revealed that the properties of the He films can be understood by a physical picture, Quantum Phase Transition between a localised solid with a gap in the excitation and a (super)fluid phase with a vanishing gap. This picture is utilised to explore and elucidate novel quantum phenomena. Experiments have been carried out in searches for (1) non-equilibrium superfluidity by phonon irradiation, (2) purely 2D 3He superfluids, and (3) possible supersolid states. While (1) and (2) are still under study, in (3) we have found that He films show anomalous dielectric behaviour. It will opens a new avenue to understanding quantum phase transitions and controlling noneequilibrium properties by an external field.

Academic Significance and Societal Importance of the Research Achievements

本研究の学術的背景は、近年の物性物理学の方向性と代表者が進めてきたヘリウム研究の整合性に基づいている。近年、トポロジーに基づく物理学が爆発的に進展しており、これまで一電子描像に留まってきたトポロジカル物質研究が、固体中電子の強相関性を取り込んでさらに発展する可能性がある。また熱平衡下では実現困難な新しい状態を非平衡下で実現する試みも、高温超伝導が観測されるなど新しい段階に入ってきた。2次元ヘリウムはこれらの概念を全て含み、トポロジカル超流動、量子液晶、外場非平衡などの新現象・新概念を示す研究対象となる。本研究は、次世代物性物理の発展に本質的寄与をなすと確信する。

Report

(5 results)
  • 2023 Final Research Report ( PDF )
  • 2022 Annual Research Report
  • 2021 Annual Research Report
  • 2020 Comments on the Screening Results   Annual Research Report
  • Research Products

    (20 results)

All 2024 2023 2022 2021 2020 Other

All Int'l Joint Research (1 results) Presentation (16 results) (of which Int'l Joint Research: 6 results,  Invited: 2 results) Remarks (2 results) Funded Workshop (1 results)

  • [Int'l Joint Research] ミュンヘン工科大学(ドイツ)

    • Related Report
      2021 Annual Research Report
  • [Presentation] Development of a nuclear adiabatic demagnetization stage using PrNi5 as cooling medium2024

    • Author(s)
      Leo Maximov, Nico Huber, Andreas Bauer, Yusuke Nago, Keiya Shirahama, and Christian Pfleiderer
    • Organizer
      International Conference on Magnetism 2024
    • Related Report
      2022 Annual Research Report
  • [Presentation] マイクロ流路中ヘリウム4超流動流の多重位相スリップ現象2024

    • Author(s)
      谷智行、和田龍馬、海谷航平、永合祐輔、村川智、白濱圭也
    • Organizer
      日本物理学会
    • Related Report
      2022 Annual Research Report
  • [Presentation] 制限空間中超流動ヘリウムにおける量子渦糸による多重位相スリップ2023

    • Author(s)
      白濱圭也
    • Organizer
      第29回渦糸物理ワークショップ
    • Related Report
      2022 Annual Research Report
  • [Presentation] ヘリウム薄膜の誘電率異常の周波数依存性2023

    • Author(s)
      小池郁也、岡村公平、永合祐輔、白濱圭也
    • Organizer
      日本物理学会
    • Related Report
      2022 Annual Research Report
  • [Presentation] Multiple phase-slip phenomenon in 4He superflow through a well-defined microchannel2023

    • Author(s)
      Keiya Shirahama
    • Organizer
      International Conference on Quantum Fluids and Solids 2023
    • Related Report
      2022 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Dielectric and elastic anomalies in helium films2023

    • Author(s)
      Keiya Shirahama
    • Organizer
      International Conference on Quantum Fluids and Solids 2023
    • Related Report
      2022 Annual Research Report
  • [Presentation] Elastic and dielectric anomalies in helium films2023

    • Author(s)
      Keiya Shirahama
    • Organizer
      Workshop Supertransport 2023
    • Related Report
      2022 Annual Research Report
  • [Presentation] Development of a miniaturized, modular, nuclear demagnetization stage2023

    • Author(s)
      Leo Maximov, Nico Huber, Andreas Bauer, Keiya Shirahama, Christian Pfleiderer
    • Organizer
      DPG Spring Meeting of the Condensed Matter Section (SKM) 2023
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 4D XY Quantum Criticality in 4He Confined in Nanoporous Media2022

    • Author(s)
      Keiya Shirahama
    • Organizer
      29th International Conference on Low Temperature Physics (LT29)
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] The Dielectric Anomaly in 4He Films2022

    • Author(s)
      Fumiya Koike, Mani Michikawa, Tomoyuki Tani, Yusuke Nago, Keiya Shirahama
    • Organizer
      29th International Conference on Low Temperature Physics (LT29)
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] The Dielectric Anomaly of Hydrogen Films2022

    • Author(s)
      Yusuke Nago, Fumiya Koike, Mani Michikawa, Tomoyuki Tani, Keiya Shirahama
    • Organizer
      29th International Conference on Low Temperature Physics (LT29)
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Observation of Phase Slippage in 4He Superflow through a Newly Developed Microslit2022

    • Author(s)
      Toyoyuki Tani, Ryoma Wada, Kohei Kaiya, Yusuke Nago, Satoshi Murakawa, Keiya Shirahama
    • Organizer
      29th International Conference on Low Temperature Physics (LT29)
    • Related Report
      2021 Annual Research Report
    • Int'l Joint Research
  • [Presentation] ヘリウム及び水素薄膜における誘電率の異常2022

    • Author(s)
      小池郁也, 道川真丹, 永合祐輔, 白濱圭也
    • Organizer
      日本物理学会第77回年次大会
    • Related Report
      2020 Annual Research Report
  • [Presentation] 水素薄膜の低温における誘電率の異常挙動2021

    • Author(s)
      白濱圭也, 道川真丹, 伊藤愛菜, 谷智行, 永合祐輔
    • Organizer
      日本物理学会2021年秋季大会
    • Related Report
      2020 Annual Research Report
  • [Presentation] 弾性異常で見たグラファイト上4He薄膜の量子相転移2020

    • Author(s)
      鈴木貴博, 巻内崇彦, 永合祐輔, 白濱圭也
    • Organizer
      日本物理学会2020年秋季大会
    • Related Report
      2020 Annual Research Report
  • [Presentation] 六方晶窒化ホウ素表面上ヘリウム4薄膜の超流動と弾性2020

    • Author(s)
      桑原啓佑, 鈴木貴博, 永合祐輔, 白濱圭也
    • Organizer
      日本物理学会2020年秋季大会
    • Related Report
      2020 Annual Research Report
  • [Remarks] 白濱研究室

    • URL

      http://www.phys.keio.ac.jp/guidance/labs/sirahama/sirahama-lab-jp.html

    • Related Report
      2022 Annual Research Report
  • [Remarks] Shirahama Group

    • URL

      http://www.phys.keio.ac.jp/guidance/labs/sirahama/sirahama-lab-jp.html

    • Related Report
      2020 Annual Research Report
  • [Funded Workshop] International Conference on Ultra Low Temperature Physics (ULT2022)2022

    • Related Report
      2021 Annual Research Report

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Published: 2020-04-28   Modified: 2025-01-30  

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