论文标题
平等时代的重力：在没有微调初始条件的情况下解决哈勃问题的解决方案
Gravity in the Era of Equality: Towards solutions to the Hubble problem without fine-tuned initial conditions
论文作者
论文摘要
宇宙扩展率（$ h_0 $）的差异测量值可能会超出标准宇宙学模型。在这里，我描述了两种早期修改的重力机制，它们通过增加物质放射平等时代的扩展率来调和$ H_0 $的价值。这些机制基于可行的Horndeski理论，所需的初始条件要比具有振荡标量磁场的早期暗能量要少得多。在平等（IDEE）的不完美的暗能量中，初始能量密度比辐射较慢，但比物质较快，自然而然地达到平等时代的峰值。最小的IDEE模型，一种立方体的Galileon，受到宇宙微波背景（Planck）和Baryon声学振荡（BAO）的约束，无法缓解$ H_0 $张力。在增强的早期重力（EEG）中，标量场值调节了重力的宇宙学强度。最小的EEG模型是一种指数耦合的立方体Galileon，给出了Planck+BAO值$ H_0 = 68.7 \ pm 1.5 $ 1.5 $（68 \％c.l.），将SH0的紧张局势从$4.4σ$降低到$2.6σ$。此外，加里隆（Galileon）对宇宙加速度的贡献可能会通过后期的幻影扩张（Lupe）调和$ H_0 $。将卢佩，脑电图和$λ$组合在一起，将普朗克，包和sh0es之间的张力降低到$2.5σ$。我还将根据局部重力测试，原始元素丰度和重力波描述耦合加油节的其他测试。尽管需要进一步的模型构建来充分解决$ H_0 $问题并满足所有可用的观察结果，但这些示例表明，解决了超越爱因斯坦一般相对论的宇宙学紧张局势的可能性。
Discrepant measurements of the Universe's expansion rate ($H_0$) may signal physics beyond the standard cosmological model. Here I describe two early modified gravity mechanisms that reconcile the value of $H_0$ by increasing the expansion rate in the era of matter-radiation equality. These mechanisms, based on viable Horndeski theories, require significantly less fine-tuned initial conditions than early dark energy with oscillating scalar fields. In Imperfect Dark Energy at Equality (IDEE), the initial energy density dilutes slower than radiation but faster than matter, naturally peaking around the era of equality. The minimal IDEE model, a cubic Galileon, is too constrained by the cosmic microwave background (Planck) and baryon acoustic oscillations (BAO) to relieve the $H_0$ tension. In Enhanced Early Gravity (EEG), the scalar field value modulates the cosmological strength of gravity. The minimal EEG model, an exponentially coupled cubic Galileon, gives a Planck+BAO value $H_0=68.7 \pm 1.5$ (68\% c.l.), reducing the tension with SH0ES from $4.4σ$ to $2.6σ$. Additionally, Galileon contributions to cosmic acceleration may reconcile $H_0$ via Late-Universe Phantom Expansion (LUPE). Combining LUPE, EEG and $Λ$ reduces the tension between Planck, BAO and SH0ES to $2.5σ$. I will also describe additional tests of coupled Galileons based on local gravity tests, primordial element abundances and gravitational waves. While further model building is required to fully resolve the $H_0$ problem and satisfy all available observations, these examples show the wealth of possibilities to solve cosmological tensions beyond Einstein's General Relativity.
