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NUMERICAL STUDY OF FINITE-TEMPERATURE LATTICE QCD

Research Project

Project/Area Number 10640246
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 素粒子・核・宇宙線
Research InstitutionUNIVERSITY OF TSUKUBA

Principal Investigator

UKAWA Akira  INSTITUTE OF PHYSICS PROFESSOR, 物理学系・計算物理学研究センター, 教授 (10143538)

Project Period (FY) 1998 – 2000
Project Status Completed (Fiscal Year 2000)
Budget Amount *help
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2000: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥1,300,000 (Direct Cost: ¥1,300,000)
KeywordsQUARK GLUON PLASMA / LATTICE QCD / FINITE TEMPERATURE / FINITE DENSITY / LATTICE GAUGE THEORY / NUMERICAL SIMULATION / HIGH ENERGY HEAVY ION SCATTERING / EARLY UNIVERSE / クォーク・グルオL・プラズマ / 量子色力学 / 相転移 / 状態方程式 / クォークゲルオンプラズマ
Research Abstract

This work aimed to elucidate the nature of the phase transition from hadron phase to quark gluon plasma phase, and physical properties of the consequent high temperature phase, using large-scale numerical simulations of quantum chromodynamics on the lattice. In the first year of the project, we investigated the properties of the phase transition itself. In the second and third years of the project, we calculated the equation of state which represent the fundamental information concerning the plasma phase. The main results we have obtained are as follows.
1. For understanding the finite-temperature phase transition of the real world, it is very important to learn how the difference of masses of the up and down quark m_<ud> and that of the strange quark m_s affects the nature of the phase transition. We have carried out a systematic determination of the line of phase transition on the (m_<ud>, m_s) plane using the Kogut-Susskind quark action, and identified the critical quark mass beyond … More which the first-order phase transition becomes absent. Further investigation of the SU (3) symmetric case has shown that the end-point of the first-order transition is a second-order transition point, and that the sigma particle becomes massless at that point.
2. Past calculations of the equation of state of the quark gluon plasma phase has exclusively used the Kogut-Susskind quark action. In our work we employed the Wilson-type quark action which is far more natural than the Kogut-Susskind quark action in the spin-flavor content. Since this calculation is CPU time intensive, being a full QCD calculation, we have exploited the use of improved actions both for the gluon and quark sectors. We adopted the integral method for calcuation of equation of state. For a methodological preparation, we first calculated the equation of state for pure gauge theory, and determined the temperature dependence of energy density and pressure. Taking the continuum limit, we obtained results for the equation of state which are in agreement with those of the standard plqquette action within 3%. For full QCD, we first determined the phase diagram on the (K,β) plane, identifying the region of parity broken phase and the critical line. We then carried out simulations on lattices with the temporal lattice size N_1=4 and 6 and the spatical size mostly 16^3. The region of quark masses corresponding to m_π/m_ρ=O.6-0.95 were explored, and the energy density and pressure were determined as a function of temperature and quark mass. The main features found in these results are (i) only weak dependence is seen once quark mass falls below m_π/m_ρ=0.9, and (ii) N_1=6 results show an approximate agreement with the continuum Stefan-Boltzmann values above T/ T_1=2. Further studies are needed to confirm and extend these results, in particulr to carry out scaling study using lattices with larger temporal sizes. Less

Report

(4 results)
  • 2000 Annual Research Report   Final Research Report Summary
  • 1999 Annual Research Report
  • 1998 Annual Research Report
  • Research Products

    (27 results)

All Other

All Publications (27 results)

  • [Publications] T.Izubuchi,J.Noaki,A.Ukawa: "Two-dimensional Lattice Gross-Neveu Model with Wilson Fermion Action at Finite Temperature and Chemical Potenatial"Physical Review D. 58. 114507 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] CP-PACS Collaboration,A.Ali Khan et al: "Equation of state in finite-temperature QCD with improved Wilson quarks"Nuclear Physics B(Proc.Suppl). 83. 360-362 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] CP-PACS Collaboration,A.Ali Khan et al: "Equation of state for pure SU(3) gauge theory with RG improved action"Nuclear Physics B(Proc.Suppl). 83. 384-386 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] CP-PACS Collaboration,M.Okamoto et al: "Equation of state for pure SU(3) gauge theory with renormalization group improved action"Physical Review D. 60. 114508 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Y.Aoki,F.Csikor,Z.Fodor,A.Ukawa: "The endpoint of the first-order phase transition of the SU(2) gauge-Higgs model on a 4-dimensional isotropic lattice"Physical Review D. 60. 013001 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] CP-PACS Collaboration,A.Ali Khan et al: "Phase structure and critical temperature of two-flavor QCD with a renormalization group improved gauge action and clover improved Wilson quark actio"Physical Review D. 63. 034502 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] S.Aoki, M.Fukugita, S.Hashimoto, K-I.Ishikawa, N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneda, S.Kaya, Y.Kuramashi, M.Okawa, T.Onogi, S.Tominaga, N.Tsutsui, A.Ukawa, N.Yamada, T.Yoshie: "Phase structure of lattice QCD at finite temperature for 2+1 flavors of Kogut-Susskind quarks"Nucl. Phys. Proc. Suppl.. 73. 459-461 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] T.Izubuchi, J.Noaki, A.Ukawa: "Two-dimensional Gross-Neveu Model with Wilson Fermion Action at Finite Temperature and Density"Nucl. Phys. Proc. Suppl.. 73. 483-485 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Y.Aoki, F.Csikor, Z.Fodor, A.Ukawa: "The end point of the first-order phase transition of the SU (2) gauge-Higgs model on a four-dimensional isotropic lattice"Nucl. Phys. Proc. Suppl.. 73. 656-658 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Taku Izubuchi, Junichi Noaki, Akira Ukawa: "Two-dimensional Lattice Gross-Neveu Model with Wilson Fermion Action at Finite Temperature and Chemical Potential"Phys. Rev.. D58. 114507 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] A.Ali Khan, S.Aoki, R.Burkhalter, S.Ejiri, M.Fukugita, S.Hashimoto, N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramashi, T.Manke, K.Nagai, M.Okamoto, M.Okawa, H.P.Shanahan, A.Ukawa, T.Yoshie: "Equation of state in finite-temperature QCD with improved Wilson quarks"Nucl. Phys. Proc. Suppl.. 83. 360-362 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] A.Ali Khan, S.Aoki, R.Burkhalter, S.Ejiri, M.Fukugita, S.Hashimoto, N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramashi, T.Manke, K.Nagai, M.Okamoto, M.Okawa, A.Ukawa, T.Yoshie: "Equation of state for pure SU (3) gauge theory with RG improved action"Nucl. Phys. Proc. Suppl.. 83. 384-386 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] M.Okamoto, A.Ali Khan, S.Aoki, R.Burkhalter, S.Ejiri, M.Fukugita, S.Hashimoto, N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramashi, T.Manke, K.Nagai, M.Okawa, A.Ukawa, T.Yoshie: "Equation of state for pure SU (3) gauge theory with renormalization group improved action"Phys. Rev. D. 60. 094510 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Y.Aoki, F.Csikor, Z.Fodor, A.Ukawa: "The endpoint of the first-order phase transition of the SU (2) gauge-Higgs model on a 4-dimensional isotropic lattice"Phys. Rev. D. 60. 013001 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] A.Ali Khan, S.Aoki, R.Burkhalter, S.Ejiri, M.Fukugita, S.Hashimoto, N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramashi, T.Manke, K.Nagai, M.Okamoto, M.Okawa, A.Ukawa, T.Yoshie: "Phase structure and critical temperature of two-flavor QCD with a renormalization group improved gauge action and clover improved Wilson quark action"Phys. Rev. D. 63. 034502 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] T.Izubuchi,J.Noaki,A.Ukawa: "Two-dimensional Lattice Gross-Neveu Model with Wilson Fermion Action at Finite Temperature and Chemical Potential"Physical Review D. 58. 114507 (1998)

    • Related Report
      2000 Annual Research Report
  • [Publications] CP-PACS Collaboration,A.Ali Khan et al: "Equation of state in finite-temperature QCD with improved Wilson quarks"Nuclear Physics B (Proc.Suppl). 83. 360-362 (1999)

    • Related Report
      2000 Annual Research Report
  • [Publications] CP-PACS Collaboration,A.Ali Khan et al: "Equation of state for pure SU(3)gauge theory with RG improved action"Nuclear Physics B (Proc.Suppl). 83. 384-386 (1999)

    • Related Report
      2000 Annual Research Report
  • [Publications] CP-PACS Collaboration,M.Okamoto et al: "Equation of state for pure SU(3)gauge theory with renormalization group improved action"Physical Review D. 60. 114508 (1999)

    • Related Report
      2000 Annual Research Report
  • [Publications] Y.Aoki,F.Csikor,Z.Fodor,A.Ukawa: "The endpoint of the first-order phase transition of the SU(2)gauge-Higgs model on a 4-dimensional isotropic lattice"Physical Review D. 60. 013001 (1999)

    • Related Report
      2000 Annual Research Report
  • [Publications] CP-PACS Collaboration,A.Ali Khan et al: "Phase structure and critical temperature of two-flavor QCD with a renormalization group improved gauge action and clover improved Wilson quark actio"Physical Review D. 63. 034502 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] M.Okamoto: "The equation of state for pure su(3) gauge theory with renormalization-group improred action"Physical review D. 60. 1-8 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] A.Ali Khan: "Equation of state for pure su(3) guage theory with RG improred action"Nucl Physics B (proc.Suppl.). 印刷中.

    • Related Report
      1999 Annual Research Report
  • [Publications] A.Ali Khan: "Equation of state in finite-temperature QCD with improved Wilson quarks"Nucl Physics (proc.Suppl.). 印刷中.

    • Related Report
      1999 Annual Research Report
  • [Publications] Y.Aoki: "The end point of the first-order phase transition of the su(2) gauge-Higgs model on a 4d lattice"Physical Review D. 60. 1-8 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] S.Aoki et al.: "Phase structure of lattice QCD at finite temperature for 2+1 flavors of Kogut-Susskind quarks" Nucl.Phys.B(Proc.Suppl.). (発表予定).

    • Related Report
      1998 Annual Research Report
  • [Publications] T.Izubuchi et al.: "Two-dimensional lattice Grass-Neuen model with Wilson action at finite temperature and chemical potential" Phys.Rev.D. 58. M4507-1-M4507-12 (1998)

    • Related Report
      1998 Annual Research Report

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Published: 1998-04-01   Modified: 2016-04-21  

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