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arXiv 2102.11792hep-phnucl-th
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2味Nambu-Jona-Lasinio模型中各向异性夸克物质的唯象研究

Phenomenological study of the anisotropic quark matter in the 2-flavor Nambu-Jona-Lasinio model

He-Xia Zhang, Yu-Xin Xiao, Jin-Wen Kang, Ben-Wei Zhang

摘要:

利用双味Nambu-Jona-Lasinio(NJL)模型对动量空间各向异性夸克物质的手征相结构、介子性质和输运性质进行了唯象研究.为了计算输运系数,我们利用了弛豫时间近似中的动力学理论,其中动量各向异性嵌入在分布函数和弛豫时间的估计中。结果表明,各向异性参数$ξ$的增加可能导致手征对称性破缺的催化作用。随着$ξ$的增加,临界端点(CEP)向更低的温度和更大的夸克化学势方向移动,动量各向异性对CEP温度和对CEP夸克化学势的影响几乎相同。介子质量和相关的衰变宽度也表现出显着的$ξ$依赖性。据观察,缩放剪切粘度$η/T^3$和缩放电导率$σ_{el}/T$的温度行为表现出类似的下降结构,随着$ξ$的增加,$η/T^3$和$σ_{el}/T$两者的最小值向更高的温度移动。此外,我们还证明了Seebeck系数$S$随温度的升高而减小,并且其符号为正,表明将温度梯度转换为电场的主要载流子是上夸克.当温度低于临界温度时,大的$ξ$显著提高了Seebeck系数$S$。

英文摘要:

With the two flavor Nambu-Jona-Lasinio (NJL) model we carry out a phenomenological study on the chiral phase structure, mesonic properties and transport properties in a momentum-space anisotropic quark matter. To calculate transport coefficients we have utilized the kinetic theory in the relaxation time approximation, where the momentum anisotropy is embedded in the estimation of both distribution function and the relaxation time. It is shown that an increase of the anisotropy parameter $ξ$ may results in a catalysis of chiral symmetry breaking. The critical endpoint (CEP) is shifted to smaller temperatures and larger quark chemical potentials as $ξ$ increases, the impact of momentum anisotropy on temperature of CEP is almost the same as that on the quark chemical potential of CEP. The meson masses and the associated decay widths also exhibit a significant $ξ$ dependence. It is observed that the temperature behavior of scaled shear viscosity $η/T^3$ and scaled electrical conductivity $σ_{el}/T$ exhibit a similar dip structure, with the minima of both $η/T^3$ and $σ_{el}/T$ shifting toward higher temperatures with increasing $ξ$. Furthermore, we demonstrate that the Seebeck coefficient $S$ decreases when temperature goes up and its sign is positive, indicating the dominant carriers for converting the temperature gradient to the electric field are up-quarks. The Seebeck coefficient $S$ is significantly enhanced with a large $ξ$ for the temperature below the critical temperature.

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