实空间和红移空间中壳交叉的影响和微扰方法的范围
Impact of shell crossing and scope of perturbative approaches in real and redshift space
摘要：
我们研究了非微扰修正对物质功率谱的影响。我们比较它们的振幅与微扰项，可以在系统的流体描述内获得，以估计这种微扰方法相关的尺度范围。我们使用简单的Zeldovich动力学作为基准，因为它允许精确计算的完整的非线性功率谱和微扰项在所有订单。然后，我们引入了一个“粘性模型”，它与Zeldovich动力学在壳交叉之前一致，但之后表现出不同的行为。因此，它们的功率谱仅在非微扰项上不同。我们考虑实空间和红移空间的功率谱。我们发现对于$Λ$ CDM宇宙学，在较高的红移下，微扰方案的势更大。对于实空间功率谱，在非微扰修正超过该阶微扰修正之前，可以在$z=3$处达到微扰理论的$66$阶，在$z=0$处达到$9$阶。这使我们能够增加上界$k$系统的理论预测，可以通过微扰计划，超出线性制度，由一个因素$\sim 26$在$z=3$和$\sim 6.5$在$z=0$。这为研究微扰再确认方案，特别是在高红移$z \geq 1$下的方案提供了强烈的动机。我们发现类似的结果红移空间功率谱，与特征波数被转移到较低的值红移空间失真放大高阶项的微扰展开，同时降低在高$k$的cummed非线性功率。
英文摘要：
We study the effect of nonperturbative corrections associated with the behavior of particles after shell crossing on the matter power spectrum. We compare their amplitude with the perturbative terms that can be obtained within the fluid description of the system, to estimate the range of scales where such perturbative approaches are relevant. We use the simple Zeldovich dynamics as a benchmark, as it allows the exact computation of the full nonlinear power spectrum and of perturbative terms at all orders. Then, we introduce a "sticky model" that coincides with the Zeldovich dynamics before shell crossing but shows a different behavior afterwards. Thus, their power spectra only differ in their nonperturbative terms. We consider both the real-space and redshift-space power spectra. We find that the potential of perturbative schemes is greater at higher redshift for a $Λ$CDM cosmology. For the real-space power spectrum, one can go up to order $66$ of perturbation theory at $z=3$, and to order $9$ at $z=0$, before the nonperturbative correction surpasses the perturbative correction of that order. This allows us to increase the upper bound on $k$ where systematic theoretical predictions may be obtained by perturbative schemes, beyond the linear regime, by a factor $\sim 26$ at $z=3$ and $\sim 6.5$ at $z=0$. This provides a strong motivation to study perturbative resummation schemes, especially at high redshifts $z \geq 1$. We find similar results for the redshift-space power spectrum, with characteristic wavenumbers that are shifted to lower values as redshift-space distortions amplify higher order terms of the perturbative expansions while decreasing the resummed nonlinear power at high $k$.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
