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Topological charges and soliton excitations protected by simmetries

Research Project

Project/Area Number 26400260
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionInstitute of Physical and Chemical Research

Principal Investigator

Ezawa Zyun Francis  国立研究開発法人理化学研究所, 仁科加速器科学研究センター, 客員研究員 (90133925)

Project Period (FY) 2014-04-01 – 2019-03-31
Project Status Completed (Fiscal Year 2018)
Budget Amount *help
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2016: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2015: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2014: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Keywordsトポロジカル量子数 / トポロジカル励起 / 場の量子論 / 対称性 / 量子ホール効果 / ゴールドストーン粒子 / スカーミオン / 量子場の理論 / 渦糸ソリトン / ゲージ理論 / ソリトン / 量子ホール系 / ゴールドストーン・モード / コヒーレント現象 / トポロジカル荷電 / 渦励起 / ワイル半金属 / 場の理論 / トポロジー / 対称性の破れ / チャーン数
Outline of Final Research Achievements

First, I investigated "symmetry protected topological systems". This concept was obtained from a development of topological insulators, while the latter concept was born from the study of quantum Hall systems. Indeed, the quantum Hall system is the first example of topological insulators. I explored the physics of Goldstone modes and topological solitons in these systems by formulating the associated topological charges and their conservation rules. I also studied how various properties of topological solitons change when the symmetry is broken. Next, I carried out my long-standing investigation of bilayer quantum Hall systems. In particular, analyzing the interaction between Goldstone modes and nuclear spins, I have derived the Dicke model familiar in quantum optics. I predicted that phenomena analogous to superradiance will be observed experimentally in the relaxation process of nuclear spins in the canted antiferromagnetic phase of the bilayer quantum Hall system.

Academic Significance and Societal Importance of the Research Achievements

トポロジカル絶縁体やエニオン量子計算機の概念は量子ホール効果の研究から発生している。今回の研究成果はトポロジカル量子物理の研究に新たな知見として寄与する。これが学術的意義であり、長期的視野で見た時の社会的意義である。さて、研究代表者は学術出版で国際的に著名なWorld Scientific社から量子ホール効果の教科書「Quantum Hall Effects」を出版している。ベストセラーとして、2000年に初版を、2008年に改定2版を、2013年に改定3版を出版している。本科研費研究の成果は準備中の改定4版に取り入れ、社会に還元したい。

Report

(6 results)
  • 2018 Annual Research Report   Final Research Report ( PDF )
  • 2017 Research-status Report
  • 2016 Research-status Report
  • 2015 Research-status Report
  • 2014 Research-status Report
  • Research Products

    (3 results)

All 2017 2016 2015

All Journal Article (1 results) (of which Peer Reviewed: 1 results,  Open Access: 1 results,  Acknowledgement Compliant: 1 results) Presentation (1 results) (of which Int'l Joint Research: 1 results) Book (1 results)

  • [Journal Article] Dicke Model for Quantum Hall Systems2016

    • Author(s)
      Y. Hama, M.H. Fauzi, K. Nemoto, Y. Hirayama, Z.F. Ezawa
    • Journal Title

      New Journal of Physics

      Volume: 18 Issue: 2 Pages: 023027-023027

    • DOI

      10.1088/1367-2630/18/2/023027

    • Related Report
      2015 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Presentation] Nuclear Spin Relaxation Induced by Linear Dispersing Nambu-Goldstone Mode in Quantum Hall Systems2015

    • Author(s)
      Y. Hama, M.H. Fauzi, K. Nemoto, Y. Hirayama, and Z.F. Ezawa
    • Organizer
      21st International Conference on Electronic Properties of Two-Dimensional Systems
    • Place of Presentation
      仙台国際センター(仙台市青葉区)
    • Year and Date
      2015-07-27
    • Related Report
      2015 Research-status Report
    • Int'l Joint Research
  • [Book] The Multifaced Skyrmion [Mannque Rho, Ismail Zahed (eds.)]2017

    • Author(s)
      Z.F. Ezawa and G. Tsitsishvili
    • Total Pages
      703
    • Publisher
      World Scientific
    • Related Report
      2016 Research-status Report

URL: 

Published: 2014-04-04   Modified: 2020-03-30  

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