论文标题
Cuscuta-Galileon宇宙学：动力学，引力“常数”和哈勃常数
Cuscuta-Galileon cosmology: Dynamics, gravitational "constant"s and the Hubble Constant
论文作者
论文摘要
我们讨论了基于Cuscuta-Galileon重力理论的宇宙学，该理论仅保留了两个自由度。尽管没有其他自由度，但引入标量场的潜力改变了动力学。标量场完全由物质字段确定。以指数的潜力为例，我们讨论了宇宙学动力。引力“常数” $ g _ {\ rm f} $出现在有效的Friedmann方程中变成时间依赖。当我们知道哈勃参数的演变时，我们还提出了如何构建潜力。当我们假设背景演化的$λ$ CDM宇宙学时，我们会找到潜在形式。 然后，我们分析了密度扰动，该方程仅以重力“常数” $ g _ {\ rm eff} $的变化为特征，这也将变得依赖时间。根据观察性约束，例如从大爆炸核合成的约束以及引力常数的时间变化的约束，我们限制了模型中的参数。 考虑到有效的弗里德曼方程中重力常数的时间依赖性，我们可能有机会解释哈勃张力问题。
We discuss cosmology based on a Cuscuta-Galileon gravity theory, which preserves just two degrees of freedom. Although there exists no additional degrees of freedom, introduction of a potential of a scalar field changes the dynamics. The scalar field is completely determined by matter fields. Giving an exponential potential as an example, we discuss the cosmological dynamics. The gravitational "constant" $G_{\rm F}$ appeared in the effective Friedmann equation becomes time dependent. We also present how to construct a potential when we know the evolution of the Hubble parameter. When we assume the $Λ$CDM cosmology for the background evolution, we find the potential form. We then analyze the density perturbations, which equation is characterized only by a change of the gravitational "constant"$G_{\rm eff}$, which also becomes time dependent. From the observational constraints such as the constraint from the big-bang nucleosynthesis and the constraint on time-variation of gravitational constant, we restrict the parameters in our models. Taking into account the time dependence of the gravitational constant in the effective Friedmann equation, we may have a chance to explain the Hubble tension problem.
