In this work, we study bulk viscous Friedmann–Robertson–Walker cosmologies with hybrid expansion law. The bulk viscous theory of dissipative effects described by Eckart theory, truncated Israel–Stewart theory and full Israel–Stewart theory are implemented here. The hybrid expansion law model of scale factor is a general analytic type of evolution from which one can recover power-law and exponential expansion as a special cases. Hybrid expansion law model are applied to describe the present accelerating phase and early phases of evolution. We have determined the cosmological parameters such as Hubble parameter, deceleration parameter, jerk parameter, energy density, bulk viscous pressure and coefficient of bulk viscosity of the universe to construct physically acceptable cosmological model. We have considered both flat and closed space–time of Friedmann–Robertson–Walker cosmology to implement hybrid expansion law with dissipative effect. The variations of the coefficient of bulk viscosity with cosmic evolution are studied here in Eckart, truncated and full Israel–Stewart theory for flat and closed space–time to obtain physically acceptable hybrid expansion models driven by viscosity. We have also estimated observational constraints of the parameters of hybrid expansion law model by considering recent observational data set. We further reveal possible connections of our models with [Formula: see text] tension problem.

中文翻译：

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具有混合膨胀定律的体粘性弗里德曼-罗伯逊-沃克宇宙学的观测约束

在这项工作中，我们研究了具有混合膨胀定律的体粘性 Friedmann-Robertson-Walker 宇宙学。Eckart 理论、截断的 Israel-Stewart 理论和完整的 Israel-Stewart 理论描述的耗散效应的体积粘性理论在此实施。比例因子的混合展开律模型是一种一般的解析演化类型，从中可以恢复幂律和指数展开作为特例。混合膨胀定律模型用于描述当前的加速阶段和早期的演化阶段。我们确定了宇宙的哈勃参数、减速参数、加加速度参数、能量密度、体积粘性压力和体积粘性系数等宇宙学参数来构建物理上可接受的宇宙学模型。我们考虑了弗里德曼-罗伯逊-沃克宇宙学的平坦时空和封闭时空，以实现具有耗散效应的混合膨胀定律。体积粘度系数随宇宙演化的变化在 Eckart 中进行了研究，截断和完整的 Israel-Stewart 理论用于平坦和封闭的时空，以获得由粘度驱动的物理上可接受的混合膨胀模型。我们还通过考虑最近的观测数据集估计了混合膨胀律模型参数的观测约束。我们进一步揭示了我们的模型与 [公式：见文本] 张力问题的可能联系。截断和完整的以色列-斯图尔特理论，用于平坦和封闭的时空，以获得由粘度驱动的物理上可接受的混合膨胀模型。我们还通过考虑最近的观测数据集估计了混合膨胀律模型参数的观测约束。我们进一步揭示了我们的模型与 [公式：见文本] 张力问题的可能联系。截断和完整的以色列-斯图尔特理论，用于平坦和封闭的时空，以获得由粘度驱动的物理上可接受的混合膨胀模型。我们还通过考虑最近的观测数据集估计了混合膨胀律模型参数的观测约束。我们进一步揭示了我们的模型与 [公式：见文本] 张力问题的可能联系。