论文标题
具有有效的流体方法的宇宙学限制，用于修饰的重力
Cosmological constraints with the Effective Fluid approach for Modified Gravity
论文作者
论文摘要
很少严格执行修饰重力（MG）模型的宇宙学约束。首先，即使一般的MG模型以不同的方式发展（即背景和扰动），但通常假设$λ$ CDM背景也是如此。这种治疗是不正确的，在精确的宇宙学时代可能会引起宇宙学参数中的不良偏见。其次，通常将中微子质量固定在分析中，这可能会掩盖其与MG参数的关系。在以前的几篇论文中，我们表明，通过使用有效的流体方法，我们可以准确地计算出相当通用的MG模型中的可观察物。我们方法的一个吸引人的优势是，它可以轻松地在Boltzmann求解器（即更少的错误 - proon）中实现此类模型，同时对有效的流体进行有用的分析描述，以了解基本的物理学。本文说明了如何使用有效的流体方法来对MG模型中的宇宙学约束进行正确的分析。我们研究了三种MG模型，包括中微子质量的总和作为我们的马尔可夫链蒙特卡洛分析中的不同参数。两种型号（即设计师$ f（r）$ [des-fr]和设计师horndeski [hdes]）具有与$λ$ cdm相匹配的背景，而在第三型型号（即Hu $ \＆$ \＆Sawicki $ f（r）$模型[HS]）中，背景与标准模型的不同之处。通过这种方式，我们估算了在限制MG参数以及中微子质量时的背景有多相关。 We implement the models in the popular Boltzmann solver CLASS and use recent, available data (i.e., Planck 2018, CMB lensing, BAO, SNIa Pantheon compilation, $H_0$ from SHOES, and RSD Gold-18 compilation) to compute tight cosmological constraints in the MG parameters that account for deviation from the $Λ$CDM model. [简略]
Cosmological constraints of Modified Gravity (MG) models are seldom carried out rigorously. First, even though general MG models evolve differently (i.e., background and perturbations) to the standard cosmological model, it is usual to assume a $Λ$CDM background. This treatment is not correct and in the era of precision cosmology could induce undesired biases in cosmological parameters. Second, neutrino mass is usually held fixed in the analyses which could obscure its relation to MG parameters. In a couple of previous papers we showed that by using the Effective Fluid Approach we can accurately compute observables in fairly general MG models. An appealing advantage of our approach is that it allows a pretty easy implementation of this kinds of models in Boltzmann solvers (i.e., less error--prone) while having a useful analytical description of the effective fluid to understand the underlying physics. This paper illustrates how an effective fluid approach can be used to carry out proper analyses of cosmological constraints in MG models. We investigated three MG models including the sum of neutrino masses as a varying parameter in our Markov Chain Monte Carlo analyses. Two models (i.e., Designer $f(R)$ [DES-fR] and Designer Horndeski [HDES]) have a background matching $Λ$CDM, while in a third model (i.e., Hu $\&$ Sawicki $f(R)$ model [HS]) the background differs from the standard model. In this way we estimate how relevant the background is when constraining MG parameters along with neutrinos' masses. We implement the models in the popular Boltzmann solver CLASS and use recent, available data (i.e., Planck 2018, CMB lensing, BAO, SNIa Pantheon compilation, $H_0$ from SHOES, and RSD Gold-18 compilation) to compute tight cosmological constraints in the MG parameters that account for deviation from the $Λ$CDM model. [abridged]
