Properties of 2+1 flavor QCD in the imaginary chemical potential region: A model approach
Properties of 2+1 flavor QCD in the imaginary chemical potential region: A model approach
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虚化学势区域中 2 1 味 QCD 的性质：模型方法
DOI：
10.1103/physrevd.96.014028
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发表时间：
2017
影响因子：
5
通讯作者：
Masanobu Yahiro
中科院分区：
文献类型：
--
作者：
Junpei Sugano;Hiraoki Kouno;Masanobu Yahiro
我们用两种方法研究了虚化学势区域中味QCD的性质。一种是基于QCD配分函数的理论方法，另一种是基于Polyakov圈扩展的Nambu-Jona-Lasinio（PNJL）模型的定性方法。在理论方法中，我们阐明了实现Roberge-Weiss（RW）周期性的虚化学势的条件。这里，是温度，指数表示味道，和是无量纲的化学势。我们还表明，RW周期性被打破，如果任何一个是固定的一个常数值。为了使这种情况形象化，我们使用PNJL模型作为具有RW周期性的模型，并在和两种情况下绘制了作为函数的相图。我们也考虑两种情况，和，这里和是无量纲常数，而和被当作变量。对于（）的某些选择，上（奇异）夸克的数密度在（）的整个区域甚至在高区域都变得平滑。这一性质对于虚化学势区域的格点QCD模拟可能是重要的，因为它使得解析延拓更加可行。
We study properties of-flavor QCD in the imaginary chemical potential region by using two approaches. One is a theoretical approach based on the QCD partition function, and the other is a qualitative one based on the Polyakov-loop extended Nambu–Jona-Lasinio (PNJL) model. In the theoretical approach, we clarify conditions imposed on the imaginary chemical potentialsto realize the Roberge-Weiss (RW) periodicity. Here,is the temperature, the indexdenotes the flavor, andare dimensionless chemical potentials. We also show that the RW periodicity is broken if any one ofis fixed to a constant value. In order to visualize the condition, we use the PNJL model as a model possessing the RW periodicity and draw the phase diagram as a function offor two conditions ofand. We also consider two cases,and; here,andare dimensionless constants, whereasandare treated as variables. For some choice of(), the number density of the up (strange) quark becomes smooth in the entire region of() even in the highregion. This property may be important for lattice QCD simulations in the imaginary chemical potential region, since it makes the analytic continuation more feasible.