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Study of QCD at low temperature and finite density with a new technique for lattice fermions

Research Project

Project/Area Number 26800154
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeMulti-year Fund
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionKochi University (2016-2017)
High Energy Accelerator Research Organization (2014-2015)

Principal Investigator

Nagata Keitaro  高知大学, 教育研究部医療学系連携医学部門, 助教 (00586901)

Project Period (FY) 2014-04-01 – 2018-03-31
Project Status Completed (Fiscal Year 2017)
Budget Amount *help
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2016: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2015: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2014: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Keywords符号問題 / 低温有限密度QCD / 有限密度QCD / 複素ランジュバン法 / シルバーブレイズ / 特異ドリフト問題に対する新解法 / 理論物理学の進展
Outline of Final Research Achievements

We have studied finite density lattice QCD, which is a longstanding issue in particle and nuclear physics, by using new techniques for lattice fermions. We first employed an approach based on a reduction formula of the lattice Wilson fermions, but it turned out to be difficult to solve an eigenvalue problem for the reduced matrix at low temperatures and finite densities. Then, we started using the Complex Langevin method(CLM), which was also a new development around 2015. We conducted theoretical studies of CLM: proof of the gauge cooling, reduction of criteria of correctness of CL simulations, and also developed a new technique with the generalization of the gauge cooling method. Based on those studies, we conducted CL simulations of QCD at low temperatures and finite densities, and achieved to simulate a targeted domain, chemical potential beyond half the pion mass, with satisfying criteria of correctness. Thus, we accomplished the purpose of this project.

Report

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

    (33 results)

All 2018 2017 2016 2015 2014

All Journal Article (16 results) (of which Peer Reviewed: 16 results,  Open Access: 12 results,  Acknowledgement Compliant: 12 results) Presentation (16 results) (of which Int'l Joint Research: 7 results,  Invited: 5 results) Funded Workshop (1 results)

  • [Journal Article] Testing the criterion for correct convergence in the complex Langevin method2018

    • Author(s)
      Keitaro Nagata, Jun Nishimura, Shinji Shimasaki
    • Journal Title

      JHEP

      Volume: 05 Issue: 5 Pages: 004-004

    • DOI

      10.1007/jhep05(2018)004

    • Related Report
      2017 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Complex Langevin simulation of QCD at finite density and low temperature using the deformation technique2018

    • Author(s)
      K.Nagata, J.Nishimura and S.Shimasaki
    • Journal Title

      EPJ Web Conf.

      Volume: 175 Pages: 07017-07017

    • DOI

      10.1051/epjconf/201817507017

    • Related Report
      2017 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] On the condition for correct convergence in the complex Langevin method2016

    • Author(s)
      S. Shimasaki, K. Nagata, J. Nishimura
    • Journal Title

      Proceedings of Science

      Volume: LATTICE2016 Pages: 071-078

    • Related Report
      2016 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Gauge cooling for the singular-drift problem in the complex Langevin method --- an application to finite density QCD2016

    • Author(s)
      K. Nagata, H. Matsufuru, J. Nishimura, S. Shimasaki
    • Journal Title

      Proceedins of Science

      Volume: LATTICE2016 Pages: 067-074

    • Related Report
      2016 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Entanglement entropy for pure gauge theories in 1+1 dimensions using the lattice regularization2016

    • Author(s)
      Sinya Aoki, Etsuko Itou, Keitaro Nagata
    • Journal Title

      IJMPA

      Volume: 31 Issue: 35 Pages: 1650192-1650192

    • DOI

      10.1142/s0217751x1650192x

    • Related Report
      2016 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Argument for justification of the complex Langevin method and the condition for correct convergence2016

    • Author(s)
      K.Nagata, J.Nishimura and S.Shimasaki,
    • Journal Title

      Phys. Rev. D

      Volume: 94, no.11 Issue: 11 Pages: 114515-114515

    • DOI

      10.1103/physrevd.94.114515

    • Related Report
      2016 Research-status Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Gauge cooling for the singular-drift problem in the complex Langevin method - a test in Random Matrix Theory for finite density QCD2016

    • Author(s)
      K.Nagata, J.Nishimura and S.Shimasaki
    • Journal Title

      JHEP

      Volume: 1607 Issue: 7 Pages: 073-073

    • DOI

      10.1007/jhep07(2016)073

    • Related Report
      2016 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Test for a universal behavior of Dirac eigenvalues in the complex Langevin method2016

    • Author(s)
      Terukazu Ichihara, Keitaro Nagata, Kouji Kashiwa
    • Journal Title

      Physical Review D

      Volume: 93 Issue: 9 Pages: 094511-094511

    • DOI

      10.1103/physrevd.93.094511

    • Related Report
      2016 Research-status Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Entanglement in Four Dimensional SU(3) gauge theory2016

    • Author(s)
      E. Itou, K. Nagata, Y. Nakagawa, A. Nakamura, V. I. Zakharov
    • Journal Title

      Prog. Theor. Exp. Phys.

      Volume: 印刷中

    • Related Report
      2015 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Testing a generalized cooling procedure in the complex Langevin simulation of chiral Random Matrix Theory2016

    • Author(s)
      K. Nagata, J. Nishimura, S. Shimasaki
    • Journal Title

      PoS LATTICE 2015

      Volume: 印刷中

    • Related Report
      2015 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Justification of the complex Langevin method with the gauge cooling procedure2016

    • Author(s)
      K. Nagata, J. Nishimura, S. Shimasaki
    • Journal Title

      Prog. Theor. Exp. Phys.

      Volume: 013B Issue: 1 Pages: 01-01

    • DOI

      10.1093/ptep/ptv173

    • Related Report
      2015 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Probing QCD phase structure using baryon multiplicity distribution2016

    • Author(s)
      A. Nakamura and K. Nagata
    • Journal Title

      Prog. Theor. Exp. Phys.

      Volume: 3 Issue: 3 Pages: 033D01-033D01

    • DOI

      10.1093/ptep/ptw013

    • Related Report
      2015 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Test for a universal behavior of Dirac eigenvalues in the complex Langevin method2016

    • Author(s)
      T. Ichihara, K. Nagata and K. Kashiwa
    • Journal Title

      Phys. Rev. D

      Volume: 印刷中

    • Related Report
      2015 Research-status Report
    • Peer Reviewed / Acknowledgement Compliant
  • [Journal Article] Net-Baryon Multiplicity and QCD phase diagram2015

    • Author(s)
      A. Nakamura, R. Fukuda, S. Oka, S. Sakai, K. Morita, K. Nagata
    • Journal Title

      PoS CPOD2014

      Volume: 2014 Pages: 021-021

    • Related Report
      2015 Research-status Report
    • Peer Reviewed
  • [Journal Article] A filtering technique for the temporally reduced matrix of the Wilson fermion determinant2015

    • Author(s)
      Y. Futamura, S. Hashimoto, A. Imakura, K. Nagata, and T. Sakurai
    • Journal Title

      PoS(LATTICE2014)

      Volume: 2015 Pages: 049-049

    • Related Report
      2014 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Journal Article] Lee-Yang zero distribution of high temperature QCD and Roberge-Weiss phase transition2015

    • Author(s)
      K. Nagata, K. Kashiwa, A. Nakamura, and S. M. Nishigaki
    • Journal Title

      Physical Review D

      Volume: 91

    • Related Report
      2014 Research-status Report
    • Peer Reviewed / Open Access / Acknowledgement Compliant
  • [Presentation] Recent progress in finite density lattice QCD towards high density2017

    • Author(s)
      Keitaro Nagata
    • Organizer
      Exploration for QCD phase diagram
    • Related Report
      2017 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] 拡張されたゲージクーリング法を用いた低温有限密度QCDの複素ランジュバンシミュレーション2016

    • Author(s)
      永田桂太郎、松古英夫、西村淳、島崎信二
    • Organizer
      日本物理学会2016秋季大会
    • Place of Presentation
      宮崎大学木花キャンパス、宮崎県、宮崎市
    • Year and Date
      2016-09-21
    • Related Report
      2016 Research-status Report
  • [Presentation] New criterion for correctness in the complex Langevin method - an application to finite density QCD2016

    • Author(s)
      K. Nagata, H. Matufuru, J. Nishimura, S. Shimasaki
    • Organizer
      XQCD 2016
    • Place of Presentation
      Plymouth, UK
    • Year and Date
      2016-08-01
    • Related Report
      2016 Research-status Report
    • Int'l Joint Research
  • [Presentation] New criterion for correctness in the complex Langevin method - an application to finite density QCD2016

    • Author(s)
      K. Nagata, H. Matufuru, J. Nishimura, S. Shimasaki
    • Organizer
      34th International Symposium on Lattice Field Theory
    • Place of Presentation
      Southampton, UK
    • Year and Date
      2016-07-24
    • Related Report
      2016 Research-status Report
    • Int'l Joint Research
  • [Presentation] 有限密度格子 QCD の最近の発展 と低温高密度への展望2015

    • Author(s)
      永田桂太郎
    • Organizer
      原子核ハドロン物理の課題と将来
    • Place of Presentation
      高エネルギー加速器研究機構(茨城県つくば市)
    • Year and Date
      2015-11-24
    • Related Report
      2015 Research-status Report
  • [Presentation] Finite density lattice QCD simulations towards QGP, heavy ion collisions, nuclear matter2015

    • Author(s)
      Keitaro Nagata
    • Organizer
      Quarks to Universe in Computational Science
    • Place of Presentation
      奈良春日野国際フォーラム 甍~I・RA・KA~(奈良県奈良市)
    • Year and Date
      2015-11-04
    • Related Report
      2015 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] A new method for fermionic singular-drift problem in the complex Langevin method2015

    • Author(s)
      Keitaro Nagata
    • Organizer
      Sign 2015
    • Place of Presentation
      MTA Atomki(Debrecen, Hungary)
    • Year and Date
      2015-09-29
    • Related Report
      2015 Research-status Report
    • Int'l Joint Research
  • [Presentation] Testing a generalized cooling procedure in the complex Langevin simulation of chiral Random Matrix Theory2015

    • Author(s)
      Keitaro Nagata
    • Organizer
      33rd International Symposium on Lattice Field Theory
    • Place of Presentation
      Kobe International Conference Center( Kobe, Japan )
    • Year and Date
      2015-07-14
    • Related Report
      2015 Research-status Report
    • Int'l Joint Research
  • [Presentation] Background of high energy physics – motivation and situation of the study of QCD2015

    • Author(s)
      Keitaro Nagata
    • Organizer
      10sor Network Workshop
    • Place of Presentation
      東京大学柏の葉フューチャーセンター(千葉県柏市)
    • Year and Date
      2015-05-14
    • Related Report
      2015 Research-status Report
    • Int'l Joint Research
  • [Presentation] 高温QCDのLee-Yangゼロ点分布2015

    • Author(s)
      Keitaro Nagata, Kouji Kashiwa, Atsushi Nakamura, Shinsuke M.Nishigaki
    • Organizer
      日本物理学会
    • Place of Presentation
      早稲田大学
    • Year and Date
      2015-03-24
    • Related Report
      2014 Research-status Report
  • [Presentation] Canonical partition functions and Lee-Yang zeros in QCD2015

    • Author(s)
      Keitaro Nagata
    • Organizer
      Hadrons and Hadron Interactions of QCD
    • Place of Presentation
      YITP, Kyoto
    • Year and Date
      2015-03-04
    • Related Report
      2014 Research-status Report
    • Invited
  • [Presentation] Lee-Yang zero distribution of high temperature QCD and Roberge-Weiss phase transition2015

    • Author(s)
      永田桂太郎
    • Organizer
      格子QCDと現象論模型による有限温度・有限密度の物理の解明
    • Place of Presentation
      九州大学
    • Year and Date
      2015-02-19
    • Related Report
      2014 Research-status Report
    • Invited
  • [Presentation] SU(3)非可換ゲージ理論におけるエンタングルメントエントロピー2014

    • Author(s)
      永田桂太郎
    • Organizer
      量子他体系の新しい潮流-テンソルネットワーク、くりこみ群、エンタングルメント
    • Place of Presentation
      京都大学基礎物理学研究所
    • Year and Date
      2014-12-15 – 2014-12-17
    • Related Report
      2014 Research-status Report
  • [Presentation] Properties of the baryon number distribution in QGP2014

    • Author(s)
      永田桂太郎
    • Organizer
      Fourth Joint Meeting of the Nuclear Physics Divisions of the APS and JPS
    • Place of Presentation
      Waikoloa Village, Hawaii
    • Year and Date
      2014-10-07 – 2014-10-11
    • Related Report
      2014 Research-status Report
  • [Presentation] Baryon number distribution in lattice QCD2014

    • Author(s)
      Keitaro Nagata
    • Organizer
      Computational Nuclear Physics II
    • Place of Presentation
      Waikoloa Village, Hawaii
    • Year and Date
      2014-10-05 – 2014-10-07
    • Related Report
      2014 Research-status Report
    • Invited
  • [Presentation] A filering technique for the temporally reduced matrix of the Wilson fermion determinant2014

    • Author(s)
      Keitaro Nagata
    • Organizer
      LATTCE 2014
    • Place of Presentation
      Columbia University, New York
    • Year and Date
      2014-06-27
    • Related Report
      2014 Research-status Report
  • [Funded Workshop] 10sor network workshop2015

    • Place of Presentation
      東京大学柏の葉フューチャーセンター
    • Year and Date
      2015-05-14
    • Related Report
      2015 Research-status Report

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Published: 2014-04-04   Modified: 2019-03-29  

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