论文标题
对数密度场的有效现场理论和扰动分析
The Effective Field Theory and Perturbative Analysis for Log-Density Fields
论文作者
论文摘要
对物质过度密度场$δ$的对数转换为功率谱带来了来自Biseptrum和高阶N点功能的信息。我们使用摄动理论（PT）计算了一个，两个和三个循环的对数转换字段$ a $的功率谱。我们将结果比较以模拟数据，并提供证据表明PT系列已经在大尺度上渐近，$ k $模式不再解散。这激发了我们为对数转换字段的替代扰动系列构建，该系列不是在$δ$的扰动之上构建的，而是直接在$ a $本身的运动方程式上。这种新方法的收敛速度更快，更好地以低$ z $为单位。然后，我们表明，可以通过少数免费参数捕获对数转换的场功率谱的大规模行为。最后，我们在有效的现场理论框架内添加了预期的反特式，并表明理论模型与IR归因过程一起，与测量的频谱相符，直到$ k \ simeq 0.38 $ mpc $^{ - 1} $ h at $ z = 0 $。它表明非线性转换确实使密度场线性化，并且原则上使我们能够访问较小尺度上包含的信息。
A logarithm transformation over the matter overdensity field $δ$ brings information from the bispectrum and higher-order n-point functions to the power spectrum. We calculate the power spectrum for the log-transformed field $A$ at one, two and three loops using perturbation theory (PT). We compare the results to simulated data and give evidence that the PT series is asymptotic already on large scales, where the $k$ modes no longer decouple. This motivates us to build an alternative perturbative series for the log-transformed field that is not constructed on top of perturbations of $δ$ but directly over the equations of motion for $A$ itself. This new approach converges faster and better reproduces the large scales at low $z$. We then show that the large-scale behaviour for the log-transformed field power spectrum can be captured by a small number of free parameters. Finally, we add the counter-terms expected within the effective field theory framework and show that the theoretical model, together with the IR-resummation procedure, agrees with the measured spectrum with percent precision until $k \simeq 0.38 $ Mpc$^{-1}$h at $z=0$. It indicates that the non-linear transformation indeed linearizes the density field and, in principle, allows us to access information contained on smaller scales.
