Bulk viscosity of two-flavor quark matter from the Kubo formalism
Bulk viscosity of two-flavor quark matter from the Kubo formalism
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DOI：
10.1103/physrevd.96.034006
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发表时间：
2017-05
影响因子：
5
通讯作者：
A. Harutyunyan;A. Sedrakian
中科院分区：
文献类型：
--
作者：
A. Harutyunyan;A. Sedrakian
在双味Nambu-Jona-Lasinio模型下，研究了强耦合区夸克物质的体粘性。导致非零体粘性的色散效应来自于高于Mott转变温度的夸克-介子涨落，其中介子衰变为两个夸克是运动学上允许的。我们采用Kubo-Zubarv形式，在$O(1/N_c)$幂计算格式中计算了压力的平衡虚时关联函数。物质的体积粘性用夸克光谱函数的洛伦兹分量来表示，它包括通过无限几何系列环图的重新求和而产生的多环贡献。结果表明，在Mott线附近，多圈贡献占主导地位，而在高温下，单圈贡献占主导地位。在Mott温度附近，多环体积粘度对剪切粘度的影响约为原来的5~20倍，但随着温度的升高，剪切粘度成为主要的应力耗散机制，单环贡献成为体积粘度的主要来源。
We study the bulk viscosity of quark matter in the strong coupling regime within the two-flavor Nambu--Jona-Lasinio model. The dispersive effects that lead to non-zero bulk viscosity arise from quark-meson fluctuations above the Mott transition temperature, where meson decay into two quarks is kinematically allowed. We adopt the Kubo-Zubarev formalism and compute the equilibrium imaginary-time correlation function for pressure in the $O(1/N_c)$ power counting scheme. The bulk viscosity of matter is expressed in terms of the Lorentz components of the quark spectral function and includes multi-loop contributions which arise via re-summation of infinite geometrical series of loop diagrams. We show that the multi-loop contributions dominate the single-loop contribution close to the Mott line, whereas at high temperatures the one-loop contribution is dominant. The multi-loop bulk viscosity dominates the shear viscosity close to the Mott temperature by factors 5 to 20, but with increasing temperature the shear viscosity becomes the dominant dissipation mechanism of stresses as the one-loop contribution becomes the main source of bulk viscosity.