有限溫度與化學勢下之夸克膠子電漿的傳輸係數

Abstract

本篇論文探討有限化學勢跟有限溫度下之夸克膠子電漿的傳輸係數包括剪切黏滯係數、體黏滯係數與傳導係數。並在等效動能理論的架構下計算這些傳輸係數。這裡探討的是弱耦合極高溫之夸克膠子電漿因此真空沒有發生自發對稱破缺。我們發現剪切黏滯係數除以熵密度的最小值發生在化學勢為零且有十六種夸克的夸克膠子電漿裡(夸克種類數的極限為十六因為那是漸進自由的極限)。對體黏滯細數來說，貝塔函數對體黏滯細數的性質有很深刻的影響，而且體黏滯細數除以熵密度的值不太隨化學勢而改變。在一個有多種夸克的夸克膠子電漿裡傳導系數被描述成一個矩陣。當化學勢為零時，這矩陣的非對角元素為零。但隨著化學勢增大，這些非對角元素會變成負值。當考慮總夸克流的傳導係數時，發現它是正的而且會隨化學勢的增大而減小。

We investigate the transport coe cients of quark-gluon plasma with nite temperature and nite chemical potential. Those transport coe cients are calculated in the framework of e ective kinetic theory. The quark-gluon plasma is assumed to be at very high temperature thus weakly-coupled and the vacuum has no spontaneous symmetry breaking. We found that the shear viscosity over entropy density (η/s) reaches its minimun when the chemical potential is zero and the avor number is large. For bulk viscosity (ζ), beta function dominates its property and ζ/s is insensitive to the chemical potential. For conductivity matrix (λ ab ), at leading-log order the o -diagonal terms is zero when the chemical potential is zero and starts to become negtive when chemical potential increases. The conductivity for total quark number (λ) is positive but decreases as chemical potential increase.