论文标题
$ f(r,t)$ gravity的晚期粘性宇宙学
Late-Time Viscous Cosmology in $f(R,T)$ Gravity
论文作者
论文摘要
本文传达了一条替代途径,以足够延迟加速,考虑到具有粘度系数$ζ=ζ_{0} +ζ_{1} h +ζ_{2} h +ζ_{2} h^{2} $的大量粘性流体,其中$ f(r,t)$修改重力。我们认为$ f(r,t)$功能形式为$ f = r+2αt$,其中$α$是一个常数。然后,我们求解哈勃参数的场方程,并研究运动学变量的宇宙学动力学,例如减速,混蛋,SNAP和LERK参数随宇宙时间的函数。我们观察到减速参数对$α$高度敏感,并在$ t \ sim 10 $ 10 $ gyrs上进行签名,$α= -0.179 $,这受到观察的青睐。我们模型的EOS参数假定$ t_ {0} = 13.7 $ gyrs的值接近$ -1 $,这与最新的Planck测量值非常一致。接下来,我们研究能量条件的演变,发现我们的模型违反了强大的能量条件,以解释延迟宇宙加速。为了理解大量的粘性重型液体模仿的暗能量的性质,我们执行了一些几何诊断,例如$ \ {r,s \} $和$ \ {r,q \} $ plane。我们发现该模型在早期模仿Chaplygin气体类型的暗能量模型的性质,而在遥远的将来的典型类型。最后,我们研究了模型的违反连续性方程的行为,并表明为了解释当前时代的宇宙加速度,能量摩托车必须违反。
The article communicates an alternative route to suffice the late-time acceleration considering a bulk viscous fluid with viscosity coefficient $ζ=ζ_{0}+ ζ_{1} H + ζ_{2} H^{2}$, where $ζ_{0}, ζ_{1}, ζ_{2}$ are constants in the framework of $f(R,T)$ modified gravity. We presume the $f(R,T)$ functional form to be $f=R+2αT$ where $α$ is a constant. We then solve the field equations for the Hubble Parameter and study the cosmological dynamics of kinematic variables such as deceleration, jerk, snap and lerk parameters as a function of cosmic time. We observe the deceleration parameter to be highly sensitive to $α$ and undergoes a signature flipping at around $t\sim 10$ Gyrs for $α=-0.179$ which is favored by observations. The EoS parameter for our model assumes values close to $-1$ at $t_{0}=13.7$Gyrs which is in remarkable agreement with the latest Planck measurements. Next, we study the evolution of energy conditions and find that our model violate the Strong Energy Condition in order to explain the late-time cosmic acceleration. To understand the nature of dark energy mimicked by the bulk viscous baryonic fluid, we perform some geometrical diagnostics like the $\{r,s\}$ and $\{r,q\}$ plane. We found the model to mimic the nature of a Chaplygin gas type dark energy model at early times while a Quintessence type in distant future. Finally, we study the violation of continuity equation for our model and show that in order to explain the cosmic acceleration at the present epoch, energy-momentum must violate.