用量子分子动力学模型研究中能重离子碰撞中的核物质约化粘滞系数

剪切粘滞系数（η）和熵密度（s）的比值,简称约化粘滞系数（η/s）,是刻画物质的一个基本输运系数,对研究核物质的液气相变及状态方程具有重要的作用。我们在同位旋依赖的量子分子动力学模型（Isospin dependent quantum molecular dynamics,IQMD）的基础上,用有限温度Thomas-Fermi理论提取中能重离子碰撞过程中的热力学性质。在此基础上分别用Green-Kubo方法及Danielewicz参数化公式来提取粘滞系数,进而得到约化粘滞系数。研究发现,随着温度或碰撞能量的增加约化粘滞系数会出现一个极小值,这与中能重离子碰撞过程中的液气相变相一致。...

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Bibliographic Details
Published in核技术 Vol. 37; no. 10; pp. 78 - 86
Main Author 周铖龙 马余刚 方德清 张国强 曹喜光
Format Journal Article
LanguageChinese
Published 中国科学院上海应用物理研究所 嘉定园区 上海201800 2014
Subjects
中能重离子碰撞
液气相变
约化粘滞系数
量子分子动力学模型
量子分子动力学模型
约化粘滞系数
Quantum molecular dynamics (QMD) model
液气相变
中能重离子碰撞
Liquid-gas phase transition
Intermediate energy heavy-ion collisions
Specific viscosity
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ISSN0253-3219
DOI10.11889/j.0253-3219.2014.hjs.37.100516

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Summary:剪切粘滞系数（η）和熵密度（s）的比值,简称约化粘滞系数（η/s）,是刻画物质的一个基本输运系数,对研究核物质的液气相变及状态方程具有重要的作用。我们在同位旋依赖的量子分子动力学模型（Isospin dependent quantum molecular dynamics,IQMD）的基础上,用有限温度Thomas-Fermi理论提取中能重离子碰撞过程中的热力学性质。在此基础上分别用Green-Kubo方法及Danielewicz参数化公式来提取粘滞系数,进而得到约化粘滞系数。研究发现,随着温度或碰撞能量的增加约化粘滞系数会出现一个极小值,这与中能重离子碰撞过程中的液气相变相一致。
Bibliography:Background： Specific viscosity, defined as the ratio of shear viscosity to entropy density, was found as a probe of phase transition. It was observed that the specific viscosity reaches a local minimum at the critical point for both macroscopic and microscopic systems. In addition, a universal lower boundary was predicted by the AdS/CFT theory. In intermediate energy heavy-ion collisions, the studies on the relationship of specific viscosity and nuclear liquid-gas phase transition are still rare. Purpose： This paper gives a brief review for our calculations of the specific viscosity of nuclear fireball created in head-on Au＋Au collisions in intermediate energy, for the study of liquid-gas phase transition. Besides, the influences of nucleon-nucleon cross section and symmetry energy on the specific viscosity are also addressed. Methods： The hot Thomas-Fermi formalism is employed to extract the thermal properties of the nuclear matter which is located in the central region of the collision. Two different method
ISSN:0253-3219
DOI:10.11889/j.0253-3219.2014.hjs.37.100516