论文标题
$λ$ CDM宇宙中的壳交叉
Shell-crossing in a $Λ$CDM Universe
论文作者
论文摘要
扰动理论是研究宇宙大规模结构的必不可少的工具，因此建立其极限至关重要。扰动理论的一个关键局限性是壳横断，这是第一次冷向黑暗轨迹相交的情况。我们在第一个壳体交叉的附近以非常高的阶层进行了Lagrangian扰动理论（LPT），以在现实的三维宇宙中进行随机初始数据。为此，我们已经为物质轨迹实现了全阶递归关系，从中建立了LPT系列的收敛性。收敛研究达到第40阶揭示了收敛限制奇异性的性质。这些奇异性不是壳交叉时众所周知的密度奇点，而是在LPT已经停止以提供物理意义的结果的后期发生。
Perturbation theory is an indispensable tool for studying the cosmic large-scale structure, and establishing its limits is therefore of utmost importance. One crucial limitation of perturbation theory is shell-crossing, which is the instance when cold-dark-matter trajectories intersect for the first time. We investigate Lagrangian perturbation theory (LPT) at very high orders in the vicinity of the first shell-crossing for random initial data in a realistic three-dimensional Universe. For this we have numerically implemented the all-order recursion relations for the matter trajectories, from which the convergence of the LPT series at shell-crossing is established. Convergence studies performed up to the 40th order reveal the nature of the convergence-limiting singularities. These singularities are not the well-known density singularities at shell-crossing but occur at later times when LPT already ceased to provide physically meaningful results.
