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What makes a phase transition genuinely quantum?-Numerical study of deconfined excitations-

Research Project

Project/Area Number 16K17762
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeMulti-year Fund
Research Field Mathematical physics/Fundamental condensed matter physics
Research InstitutionThe University of Tokyo

Principal Investigator

Suwa Hidemaro  東京大学, 大学院理学系研究科(理学部), 助教 (60735926)

Project Period (FY) 2016-04-01 – 2019-03-31
Project Status Completed (Fiscal Year 2018)
Budget Amount *help
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Keywords量子臨界 / 脱閉じ込め / スピノン / 分数励起 / 量子モンテカルロ / スペクトル / 対称性 / 量子モンテカルロ法 / ワームアルゴリズム / 幾何学的配分法 / 創発 / 閉じ込め / モンテカルロ / ランダウ理論 / J-Q模型 / 物性物理学 / 計算物理学 / 量子相転移
Outline of Final Research Achievements

Phase transitions and critical phenomena emerging in strongly correlated systems are central topics in statistical mechanics. The Landau theory, which is a standard theory of phase transitions, accounts for many properties of actual phase transitions including many quantum phase transitions. In the meantime, the deconfined quantum criticality has caught the attention as a nontrivial phenomenon rendering a phase transition genuinely quantum beyond the Landau paradigm. At this unusual criticality, deconfined fractional excitations are predicted by an effective field theory. We have studied the deconfined quantum criticality appearing in a two-dimensional quantum spin system using the path-integral quantum Monte Carlo method and elucidated the characteristic spectrum of fractional excitations.

Academic Significance and Societal Importance of the Research Achievements

本研究のテーマは、相転移の基礎理論を超える量子相転移の物理を明らかにする点で、統計力学の最も重要な問題のひとつと言える。本課題は、新しい計算手法を開発しながら、非自明な量子相転移での分数励起(通常現れる粒子がいくつかに別れる励起)を初めて明らかにした。我々は励起エネルギーを高精度で見積もる計算法を開発し、量子モンテカルロ法によるエネルギーギャップ解析を確立させた。この手法を武器として2次元量子スピン系を解析し、分数励起の線形分散関係を明らかにした。本研究は相転移の基礎理論を超える臨界現象における励起状態を明らかにした点で、統計力学と物性物理の発展に大きく貢献する。

Report

(5 results)
  • 2018 Annual Research Report   Final Research Report ( PDF )
  • 2017 Research-status Report
  • 2016 Research-status Report
  • Products Report
  • Research Products

    (15 results)

All 2021 2020 2018 2017 2016 Other

All Int'l Joint Research (2 results) Journal Article (3 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 3 results,  Acknowledgement Compliant: 2 results) Presentation (10 results) (of which Int'l Joint Research: 6 results,  Invited: 5 results)

  • [Int'l Joint Research] インド科学振興協会(インド)

    • Related Report
      2016 Research-status Report
  • [Int'l Joint Research] ボストン大学(米国)

    • Related Report
      2016 Research-status Report
  • [Journal Article] Geometric allocation approach to accelerating directed worm algorithm2021

    • Author(s)
      Hidemaro Suwa
    • Journal Title

      Physical Review E

      Volume: 103 Issue: 1 Pages: 013308-013308

    • DOI

      10.1103/physreve.103.013308

    • Related Report
      Products Report
    • Peer Reviewed
  • [Journal Article] Upper and lower critical decay exponents of Ising ferromagnet with long-range interaction2017

    • Author(s)
      Toshiki Horita, Hidemaro Suwa, Synge Todo
    • Journal Title

      Phys. Rev. E

      Volume: 95 Issue: 1 Pages: 012143-012143

    • DOI

      10.1103/physreve.95.012143

    • Related Report
      2016 Research-status Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Level spectroscopy in a two-dimensional quantum magnet: Linearly dispersing spinons at the deconfined quantum critical point2016

    • Author(s)
      Hidemaro Suwa, Arnab Sen, Anders W. Sandvik
    • Journal Title

      Physical Review B

      Volume: 94 Issue: 14 Pages: 144416-144416

    • DOI

      10.1103/physrevb.94.144416

    • Related Report
      2016 Research-status Report
    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Presentation] How to play geometric puzzles for efficient Monte Carlo updates2020

    • Author(s)
      Hidemaro Suwa
    • Organizer
      School on algorithms in lattice gauge theory and spin systems
    • Related Report
      Products Report
  • [Presentation] How Can We Guide the Worm in a Lattice Model?2018

    • Author(s)
      Hidemaro Suwa
    • Organizer
      2nd Critical Behavior in Lattice Models
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Linearly dispersing spinons at the deconfined quantum critical point2017

    • Author(s)
      Hidemaro Suwa, Arnab Sen, Anders W. Sandvik
    • Organizer
      APS March Meeting 2017
    • Place of Presentation
      ニューオーリンズ(アメリカ)
    • Year and Date
      2017-03-13
    • Related Report
      2016 Research-status Report
    • Int'l Joint Research
  • [Presentation] Worm algorithm with geometric optimization and deconfined spinons at Neel-VBS Transition2017

    • Author(s)
      Hidemaro Suwa
    • Organizer
      Frustrated Magnetism
    • Related Report
      2017 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Spinon dispersion at deconfined quantum critical point2016

    • Author(s)
      Hidemaro Suwa, Arnab Sen, Anders W. Sandvik
    • Organizer
      1st International Symposium on Research and Education of Computational Science
    • Place of Presentation
      東京大学(東京都・文京区)
    • Year and Date
      2016-11-29
    • Related Report
      2016 Research-status Report
    • Int'l Joint Research
  • [Presentation] Neel-VBS 転移におけるマルチギャップレス励起モード2016

    • Author(s)
      諏訪秀麿、Arnab Sen、Anders W. Sandvik
    • Organizer
      日本物理学会 2016年秋季大会
    • Place of Presentation
      金沢大学(石川県・金沢市)
    • Year and Date
      2016-09-13
    • Related Report
      2016 Research-status Report
  • [Presentation] Quantum Monte Carlo Analysis of Linearly Dispersing Spinons at Deconfined Quantum-Critical Point2016

    • Author(s)
      Hidemaro Suwa
    • Organizer
      CNLS Seminar
    • Place of Presentation
      ロスアラモス(アメリカ)
    • Year and Date
      2016-08-25
    • Related Report
      2016 Research-status Report
    • Invited
  • [Presentation] Linearly Dispersing Spinons at the Deconfined Quantum Criticality2016

    • Author(s)
      Hidemaro Suwa
    • Organizer
      Quantum Criticality and Topology in Itinerant Electron Systems
    • Place of Presentation
      アルバカーキ(アメリカ)
    • Year and Date
      2016-08-15
    • Related Report
      2016 Research-status Report
    • Int'l Joint Research
  • [Presentation] Quantum Monte Carlo Analysis of Linearly Dispersing Spinons at Deconfined Quantum-Critical Point2016

    • Author(s)
      Hidemaro Suwa
    • Organizer
      Riken Seminar
    • Place of Presentation
      理化学研究所(埼玉県・和光市)
    • Year and Date
      2016-08-01
    • Related Report
      2016 Research-status Report
    • Invited
  • [Presentation] Multiple Gapless-Excitation Modes at Neel to Valence-Bond-Solid Transition2016

    • Author(s)
      Hidemaro Suwa
    • Organizer
      2nd Conference on Condensed Matter Physics
    • Place of Presentation
      南京(中国)
    • Year and Date
      2016-07-21
    • Related Report
      2016 Research-status Report
    • Int'l Joint Research / Invited

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Published: 2016-04-21   Modified: 2024-03-28  

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