标题： 晚时期宇宙学解在粘性宇宙中的$f(R,T)$引力理论中 显示英文标题

标题： Late time cosmological solutions in $f(R,T)$ gravity in a viscous Universe

摘要： 考虑到能量动量张量（EMT）的守恒条件，我们在平坦的FLRW时空背景下研究了$f(R,T)=R+\alpha T^{n}$引力理论（其中$\alpha$和$n$是常数）中的晚期宇宙学解。 当前模型讨论了宇宙物质内容为广义的理想流体的情况，以及考虑耗散效应的情况。 简而言之，假设单一的理想流体，我们发现所述模型无法提供宇宙晚期加速膨胀的观测一致图像；然而，当考虑体积粘滞时，该模型会导致可接受的解。 在这方面，考虑到Eckart、截断和完整Israel-Stewart理论，找到了一致的设置，这些理论决定了体积粘滞的行为。 在存在体积粘滞的情况下，减速参数（DP）的行为表明，即使宇宙物质内容的各向同性压力可以忽略不计，该基础模型仍可以描述一个可接受的演化过程。 显示英文摘要

摘要： Considering the condition on conservation of energy momentum tensor (EMT), we study late time cosmological solutions in the context of $f(R,T)=R+\alpha T^{n}$ gravity (where $\alpha$ and $n$ are constants) in a flat FLRW spacetime. The present model discusses the case of a barotropic perfect fluid as the matter content of the Universe, along with the case when dissipative effects are taken into account. Briefly, assuming a single perfect fluid we find that the mentioned model is not capable of presenting an observationally consistent picture of the late time accelerated expansion of the Universe; nevertheless, the model leads to admissible solutions when the bulk viscosity is included. In this regard, a consistent setting is found considering the Eckart, Truncated and Full Israel-Stewart theories which determine the behavior of bulk viscosity. In the presence of bulk viscosity, the behavior of the deceleration parameter (DP) shows that the underlying model can describe an acceptable evolution even if the isotropic pressure of matter content of the Universe is negligible.