论文标题
暗能量密度，是（以色列 - 史图尔特）散装粘度模型
Dark Energy Density and IS (Israel-Stewart) Bulk Viscosity Model
论文作者
论文摘要
我们将深色能量大块粘度模型的热力学作为宇宙流体。在这方面，Eckart和以色列 - 斯图尔特（IS）的两种理论是我们工作的基础。因此，我们首先研究了深色能量粘度模型和一般关系中宇宙流体的热力学。然后，我们表达了Eckart理论的热力学关系。由于Eckart理论和弗里德曼方程的基本方程式，我们考虑两个状态，一个是$ p =-ρ$（标准），另一个是$ p \ neq-ρ$（非标准）。在标准状态下，我们在宇宙时间上定义了压力$（p）$，能量密度$（ρ）$（ρ）$（ρ）$（ρ）$（ρ）$（ξ）$，我们获得了其关系。我们还提到，在此标准状态下，由于$ p =-ρ$，$ a（t）$的值为零，因此在此状态下未定义$ a（t）$。但是，在非标准情况下，$（p \ neq-ρ）$散装粘度系数$（ξ）$为零，只有宇宙流体的比例因子和压力和能量密度才能定义。我们还考虑了两种恒定和可变的体积粘度系数的状态，并以宇宙时间和尺度因子的范围来获得三个哈勃恒定参数和比例因子。在可变的大量粘度系数的状态下，我们将粘度系数视为能量密度$（ξ=αρ^{s}）$的幂律，即$α> 0 $和一个常数。随后，我们讨论了宇宙流体的耗散作用，并检查了以色列 - 斯图尔特（IS）理论中深色能量的能量密度的影响。结果全面显示在两个表（1）和（2）中。
We investigate the thermodynamics of a dark energy bulk viscosity model as a cosmic fluid. In this regard, the two theories of Eckart and Israel-Stewart (IS) are the basis of our work. Therefore, we first investigate the thermodynamics of cosmic fluids in the dark energy bulk viscosity model and the general relationships. Then, we express the thermodynamic relationships of Eckart's theory. Due to the basic equations of Eckart's theory and Friedmann's equations, we consider two states, one is $p=-ρ$ (standard) and the other is $p\neq-ρ$ (non-standard). In the standard state, we define the pressure $(p)$, energy density $(ρ)$, and bulk viscosity coefficient $(ξ)$ of the cosmic fluid in terms of cosmic time and we obtain its relations. We also mention that in this standard state, because of $p=-ρ$, the value of $a(t)$ is zero, so $a(t)$ is not defined in this state. But in the non-standard case $(p\neq-ρ)$ the bulk viscosity coefficient $(ξ)$ is zero and only the scale factor and pressure and energy density of the cosmic fluid is defined. We also consider two states of constant and variable bulk viscosity coefficients and obtain three Hubble constant parameters and scale factors in terms of cosmic time, and energy density in terms of the scale factor. In the state of variable bulk viscosity coefficient, we consider the viscosity coefficient as the power-law from energy density $(ξ=αρ^{s})$, which is $α>0$ and a constant. Following, we discuss the dissipative effects of cosmic fluids and examine the effects of energy density for dark energy in the Israel-Stewart(IS) theory. The results are comprehensively presented in two tables (1) and (2).
