论文标题
$ f(t)$ gravity中的粘性宇宙学
Viscous cosmology in $f(T)$ gravity
论文作者
论文摘要
我们为宇宙物质的粘度提出了一个新模型,该模型可以应用于宇宙的不同时期。使用此模型,我们将散装粘度作为对重型和暗物质的完美流体模型的实际校正,因为现实世界中的材料流体可能由于热力学而具有粘度。在$ f(t)$重力的框架内,将这种包容性用于描述宇宙加速度的成功,其中$ t $表示扭转标量。我们对模型进行观察拟合,并通过使用各种最新的宇宙学数据集来限制宇宙学和模型参数。基于拟合结果,我们讨论了几种宇宙学的含义,包括物质的耗散,宇宙的进化历史,$ f(t)$修饰作为有效的暗能量以及哈勃的张力问题。相应的发现是(i)较晚的耗散将使事项的密度参数在有限的未来消失。此外,随着时间的推移,重型和暗物质之间的密度比将变化。 (ii)可以恢复辐射主导时代,物质主导时代和加速时代,模型可以成功地描述宇宙的已知历史。 (iii)$ f(t)$修改是加速扩展的主要驱动器,目前模仿了幻影般的暗能量。但是宇宙最终将进入DE Sitter扩展阶段。 (iv)在我们的模型中可以显着缓解本地和全球观察之间的哈勃张力。
We propose a new model for the viscosity of cosmic matters, which can be applied to different epochs of the universe. Using this model, we include the bulk viscosities as practical corrections to the perfect fluid models of the baryonic and dark matters since the material fluids in the real world may have viscosities due to thermodynamics. Such inclusion is put to the test within the framework of $f(T)$ gravity that is proved to be successful in describing the cosmic acceleration, where $T$ denotes the torsion scalar. We perform an observational fit to our model and constrain the cosmological and model parameters by using various latest cosmological datasets. Based on the fitting result, we discuss several cosmological implications including the dissipation of matters, the evolutionary history of the universe, $f(T)$ modification as an effective dark energy, and the Hubble tension problem. The corresponding findings are (i) The late time dissipation will make the density parameters of the matters vanish in the finite future. Moreover, the density ratio between the baryonic and dark matters will change over time. (ii) The radiation dominating era, matter dominating era and the accelerating era can be recovered and the model can successfully describe the known history of the universe. (iii) The $f(T)$ modification is the main drive of the acceleration expansion and currently mimics a phantom-like dark energy. But the universe will eventually enter a de Sitter expansion phase. (iv) The Hubble tension between local and global observations can be significantly alleviated in our model.