论文标题
标量上的贝叶斯模型选择$ε$ - 场暗能量
Bayesian model selection on Scalar $ε$-Field Dark Energy
论文作者
论文摘要
本文的主要目的是分析最小耦合的标量场（典型和幻影），作为解释宇宙加速扩张的主要候选者，并将其可观察到的物品与当前的宇宙学观察结果进行比较；作为副产品，我们提出其Python模块。这项工作包括一个参数$ε$，该参数允许将典型和幻影字段同时纳入相同的分析中。到目前为止，该电位的示例是$ v（ϕ）= v_0d =^^{βϕ^α} $和$ v（ϕ）= v_0（\ cosh（αx）+β）$，$α$，$ $，$μ$ $和$β$是免费的参数，但分析很容易扩展到任何其他范围。除现场成分和物质的标准内容外，该研究还纳入了空间曲率（$ω_K$）的贡献，因为它一直是最近研究的重点。该分析包含最新的数据集以及嵌套采样器，以产生后验分布以及贝叶斯证据，从而可以执行模型选择。在这项工作中，我们限制了描述两个通用电势的参数空间，在几种组合中，我们发现，当前数据集的最佳拟合是由一个略有利于潜在$ v（ϕ）= v_0 ϕ^μE^μe^{β{β= 0.22 \ pm 1.56 $ 1.56 $，$ cur的模型给出的模型。 $ω_{k，0} = -0.0016 \ pm0.0018 $，其偏离$1.6σ$与标准$λ$ CDM型号的偏差。即使该潜力包含三个额外的参数，贝叶斯证据$ \ MATHCAL {B} _ {λ，ϕ} = 2.0 $与具有曲率的$λ$ CDM相比，该模型无法区分该模型（$ω___________，0} = 0.0013 \ pm0.0018 $）。提供最小贝叶斯证据的潜力对应于$ v（ϕ）= v_0 \ cosh（αd）$，$α= -0.61 \ pm 1.36 $。
The main aim of this paper is to analyse minimally-coupled scalar-fields -- quintessence and phantom -- as the main candidates to explain the accelerated expansion of the universe and compare its observables to current cosmological observations; as a byproduct we present its python module. This work includes a parameter $ε$ which allows to incorporate both quintessence and phantom fields within the same analysis. Examples of the potentials, so far included, are $V(ϕ)=V_0ϕ^μe^{βϕ^α}$ and $V(ϕ)=V_0(\cosh(αϕ)+β)$ with $α$, $μ$ and $β$ being free parameters, but the analysis can be easily extended to any other scalar field potential. Additional to the field component and the standard content of matter, the study also incorporates the contribution from spatial curvature ($Ω_k$), as it has been the focus in recent studies. The analysis contains the most up-to-date datasets along with a nested sampler to produce posterior distributions along with the Bayesian evidence, that allows to perform a model selection. In this work we constrain the parameter-space describing the two generic potentials, and among several combinations, we found that the best-fit to current datasets is given by a model slightly favouring the quintessence field with potential $V(ϕ)=V_0ϕ^μe^{βϕ}$ with $β=0.22\pm 1.56$, $μ= -0.41\pm 1.90$, and slightly negative curvature $Ω_{k,0}=-0.0016\pm0.0018$, which presents deviations of $1.6σ$ from the standard $Λ$CDM model. Even though this potential contains three extra parameters, the Bayesian evidence $\mathcal{B}_{Λ, ϕ} =2.0$ is unable to distinguish this model compared to the $Λ$CDM with curvature ($Ω_{k,0}=0.0013\pm0.0018$). The potential that provides the minimal Bayesian evidence corresponds to $V(ϕ)=V_0 \cosh(αϕ)$ with $α=-0.61\pm 1.36$.
