论文标题
使用机器学习来压缩物质传输功能$ t(k)$
Using machine learning to compress the matter transfer function $T(k)$
论文作者
论文摘要
线性物质功率谱$ P(K,Z)$将理论与宇宙学中的大规模结构观测联系起来。它的比例依赖性完全编码在物质传输函数$ t(k)$中,该$可以由Boltzmann求解器数值计算,也可以通过使用拟合函数(例如著名的Bardeen-Bond-Kaiser-Szalay(BBKS)和Eisenstein-Hu(Eh(EH)(eH)形式进行半分析计算。但是,BBK和EH公式都有一些重要的缺点。一方面,尽管BBK是一个简单的表达式,但它仅准确至$ 10 \%$,远高于即将进行的调查的$ 1 \%$精确目标。另一方面,尽管EH是即将进行的实验所需的准确性,但它是一个相当长且复杂的表达。在这里,我们使用一种特定的机器学习技术遗传算法(GAS)来得出传输函数$ t(k)$的简单准确的拟合公式。当还考虑了大规模中微子的影响时,我们的表达在EH公式上略有改善,而相比之下,我们的表达却大大缩短。
The linear matter power spectrum $P(k,z)$ connects theory with large scale structure observations in cosmology. Its scale dependence is entirely encoded in the matter transfer function $T(k)$, which can be computed numerically by Boltzmann solvers, and can also be computed semi-analytically by using fitting functions such as the well-known Bardeen-Bond-Kaiser-Szalay (BBKS) and Eisenstein-Hu (EH) formulae. However, both the BBKS and EH formulae have some significant drawbacks. On the one hand, although BBKS is a simple expression, it is only accurate up to $10\%$, which is well above the $1\%$ precision goal of forthcoming surveys. On the other hand, while EH is as accurate as required by upcoming experiments, it is a rather long and complicated expression. Here, we use the Genetic Algorithms (GAs), a particular machine learning technique, to derive simple and accurate fitting formulae for the transfer function $T(k)$. When the effects of massive neutrinos are also considered, our expression slightly improves over the EH formula, while being notably shorter in comparison.