arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1012.0546astro-ph.COgr-qc
收藏

重子声学振荡的紧耦合近似

The tight-coupling approximation for baryon acoustic oscillations

Cyril Pitrou

摘要:

紧耦合近似(TCA)用于描述重子-光子系统的早期动力学,系统地建立了更高的相互作用率的倒数的订单。这种扩展可以用来掌握的物理效应,通过推导简单的解析解,或获得一种形式的系统,这是稳定的数值在早期。在线性宇宙学扰动中,我们用数值方法估计了它的精度,并讨论了它对重子声学振荡的影响。TCA可以推广到二阶宇宙学扰动,特别是我们恢复了涡不产生在这种膨胀的最低阶。

英文摘要:

The tight-coupling approximation (TCA) used to describe the early dynamics of the baryons-photons system is systematically built to higher orders in the inverse of the interaction rate. This expansion can be either used to grasp the physical effects by deriving simple analytic solutions or to obtain a form of the system which is stable numerically at early times. In linear cosmological perturbations, we estimate numerically its precision, and we discuss the implications for the baryons acoustic oscillations. The TCA can be extended to the second order cosmological perturbations, and in particular we recover that vorticity is not generated at lowest order of this expansion.

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。

↑