Quark-Gluon Systems at Extreme Condition: International Collaboration for High Temperature and Density QCD

极端条件下的夸克-胶子系统：高温和密度 QCD 的国际合作

• 批准号: 17340080
• 负责人: NAKAMURA Atsushi
• 金额: $ 7.51万
• 依托单位: Hiroshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17340080/
• 关键词: quarks; gluons; QGP; confining; QCD; クォーク・グルーオン・プラズマ; 格子ゲージ理論; シミュレーション; 輸送係数; 国際共同研究; 極限状態

1) At RBHIC, a new form of matter was created. It is important to understand this new matter by lattice QCD, the first-principle calculation. We calculated the shear viscosity of quark-gluon plasma in detail by lattice QCD and found that it is very small and the matter is almost perfect fluid, which is suggested by experiments.2) We proceed the above calculation, and showed that the bulk-viscosity is very small but positive definite.3) We calculated quark-propagators in both the confinement and the deconfinement phases. We observed that the spectrum is not positive definite in the confinement phase. Quark mass is difkent in the confinement and deconfmment phases. Especially in the deconfinement phase, a standard form does not work.4) At very high temperature, the confinement is expected to be broken. To understand this phenomena, it is important to understand the confinement mechanism at zero temperature. For this purpose, using the Coulomb gauge, which is the physical gauge, we calculated the color-Coulomb form numerically. We observed that the confinement force comes from the color-Coulomb force, and relates to the behavior of eigen values of the Fadddev-Popov operators. However, the temperature behavior of the eigen values is different from what was expected, ie., the condensation of the eigen-values near zero does not disappear. The confinement/deconfinement transition is very non-trivial.5) We developed a Lattice QCD code on the CELTLL which is a new architecture of high-performance computers.

1)在RBHIC，一种新的物质形式被创造出来。通过格点QCD（第一性原理计算）来理解这种新物质是很重要的。用格点QCD方法详细计算了夸克胶子等离子体的剪切粘滞系数，发现它很小，物质几乎是理想流体，这与实验结果一致; 2）继续进行上述计算，发现体粘滞系数很小，但为正; 3）计算了禁闭相和解除禁闭相的夸克传播子.我们观察到，在限制阶段的频谱是不正定的。夸克的质量在禁闭和退禁闭阶段是不同的。特别是在解除禁闭阶段，标准形式不起作用。4）在非常高的温度下，禁闭预计将被打破。为了理解这种现象，重要的是要理解零温度下的约束机制。为此，我们利用库仑规范，这是物理规范，数值计算的颜色库仑形式。我们观察到，约束力来自色库仑力，并与Fadddev-Popov算子的本征值的行为有关。然而，本征值的温度行为与预期的不同，即，接近零的本征值的凝聚不会消失。5）在CELTLL上开发了一个格点QCD程序。

项目成果

I=1/2 Scalar and Axial Vector Mesons

I=1/2 标量和轴向矢量介子

• 发表时间: 2005
• 期刊: PoS LAT2005
• 作者: R. Sugahara;et. al.;Keiju Murata;A. Noda;M. Sekiguchi
• 通讯作者: M. Sekiguchi

格子QCD計算とハドロン・原子核物理

晶格 QCD 计算和强子/核物理

• 发表时间: 2008
• 作者: Hidenori Nomura;Misao Sasaki and Kazuhiro Yamamoto;中村純
• 通讯作者: 中村純

Lattice Study of Gluon Viscosities - A Step Towards RHIC Physics

胶子粘度的晶格研究 - 迈向 RHIC 物理的一步

• 发表时间: 2006
• 期刊: Acta Physica Polonica B 37
• 作者: A. Nakamura;S. Sakai
• 通讯作者: S. Sakai

COLOR CONFINEMENT IN COULOMB GAUGE QCD

库仑计 QCD 中的颜色限制

• 发表时间: 2006
• 期刊: Prog. Theor. Phys. 115
• 作者: R. Sugahara;M. Nozaki;S. Takeda;H. Yamaoka;S. Yamashita and Y. Nakayama;Atsushi Nakamura
• 通讯作者: Atsushi Nakamura

Zwanziger Properties of Color-Coulomb String Tension

颜色-库仑弦张力的 Zwanziger 特性

• 发表时间: 2006
• 期刊: Phys. Rev. D 73
• 作者: Y. Nakagawa;A. Nakamura;T. Saito;H. Toki;D.
• 通讯作者: D.