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Study on the character of elementary excitations around critical point of QCD phase transitions

QCD相变临界点附近基元激发特性研究

基本信息

批准号：
17540250
负责人：
KUNIHIRO Teiji
金额：
$ 1.95万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
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

项目摘要

We have shown that the quarks around the chiral transition at finite temperature can change their quasi-particle picture owing to the coupling to the chiral soft modes. Around the critical point, there may appear soft modes which are coupled to the fluctuations of the order parameter of the phase transition. We have investigated the quark self-energy due to this bosonic mode at finite temperature. We have shown that the spectral function of the quark gets to have three peaks in the low-energy region : The two of them existing in the positive-and negative-energy regions correspond to the normal-quark and plasmino excitations familiar in the hard-thermal loop approximation valid in the extremely high-temperature region. We have shown that there appears an additional excitation with a vanishingly small energy. We have clarified the mechanism for the formation of such a multiple peak structure in terms of the level crossing between the quark and the thermally excited anti-quarks. We have also shown that such a realization of the three-peak structure does not depend on the type of the bosonic excitation, i.e., it may be vector or axial vector type. We have also identified the poles corresponding to the three peaks, and examined the temperature dependence of the poles. We have found that the set of the three trajectories changes its structure in a drastic way when the quak mass is raised.We have tried to construct sensible hydrodynamic equations for viscous fluids using the so called renormalization-group method. We have shown that the obtained equation in the particle fame does not show a pathological behavior unlike to the original Eckart equation.

我们已经证明，在有限温度下，手性跃迁周围的夸克由于与手性软模式的耦合而改变了它们的准粒子图像。在临界点附近，可能出现与相变序参量波动相耦合的软模。我们研究了有限温度下由玻色子模式引起的夸克自能。我们已经证明，夸克的谱函数在低能区有三个峰：其中两个峰存在于正能量区和负能量区，对应于在极高温区域有效的硬热环近似中常见的正夸克和纤溶酶激发。我们已经证明，存在一个能量极小的附加激发。我们从夸克与热激发反夸克之间的水平交叉角度阐明了这种多峰结构形成的机理。我们还证明了这种三峰结构的实现不依赖于玻色子激励的类型，即可以是矢量型或轴向型。我们还确定了三个峰对应的极点，并检查了极点对温度的依赖性。我们发现，当地震质量上升时，这三种轨迹的集合以一种剧烈的方式改变了它的结构。我们尝试用所谓的重整化群方法来构造粘性流体的合理流体动力学方程。我们已经证明，在粒子名气中得到的方程并没有表现出与原始Eckart方程不同的病理行为。