论文标题
一阶通用粘性流体动力学的宇宙学后果
Cosmological consequences of first-order general-relativistic viscous fluid dynamics
论文作者
论文摘要
我们使用最一般的因果和稳定的粘性能量巨孔量张量在时空衍生物中定义的最一般和稳定的粘性能量量张量，研究了空间平坦的Friedmann-Lema-Robertson-Walker宇宙学中粘性流体的平衡动力学。在这个新框架中，具有密度$ρ$的无压力粘性流体可以演变为渐近的未来解决方案，在该解决方案中，哈勃参数接近常数，而$ρ\ rightarrow 0 $，即使在没有宇宙学常数的情况下（即$λ= 0 $）。因此，尽管该模型中的粘性效应驱动了宇宙的加速膨胀，但粘性成分的密度本身就消失了，仅留下加速度。这种行为是由于因果关系在相对论流体动力学的一阶理论中出现的，并且与爱因斯坦的方程式完全一致。
We investigate the out-of-equilibrium dynamics of viscous fluids in a spatially flat Friedmann-Lemaître-Robertson-Walker cosmology using the most general causal and stable viscous energy-momentum tensor defined at first order in spacetime derivatives. In this new framework a pressureless viscous fluid having density $ρ$ can evolve to an asymptotic future solution in which the Hubble parameter approaches a constant while $ρ\rightarrow 0$, even in the absence of a cosmological constant (i.e., $Λ= 0$). Thus, while viscous effects in this model drive an accelerated expansion of the universe, the density of the viscous component itself vanishes, leaving behind only the acceleration. This behavior emerges as a consequence of causality in first-order theories of relativistic fluid dynamics and it is fully consistent with Einstein's equations.
