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arXiv 2202.09356astro-ph.COgr-qc
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根据宇宙学张力对早期引力跃迁的探索

An exploration of an early gravity transition in light of cosmological tensions

Giampaolo Benevento, Joshua A. Kable, Graeme E. Addison, Charles L. Bennett

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Small additions to the tables, discussion and bibliography, results unchanged, matches version published in Apj
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摘要：

我们研究了在复合之前宇宙学尺度上有效普朗克质量（或有效引力常数）值的阶跃式转变。我们采用CMB，BAO和SNIa数据，并发现它们足以强烈约束我们的实施的有效场理论的暗能量和修正的重力，用于模拟过渡，到一个有限的参数空间。数据倾向于在复合之前有效普朗克质量值（$2 σ$处的$<10 \%$）的$\sim 5\%$位移。这个过渡普朗克质量（TPM）模型是自由的，在重组之前，$\log_{10}(a) = -5.32^{+0.96}_{-0.72}$（68\% CL）的标度因子的几十年内的任何点进行其过渡。这降低了最后散射时的声视界，这将哈勃常数增加到$71.09 \pm 0.75$ km $\textrm{s}^{-1}\textrm{Mpc}^{-1}$，并结合当地测量作为先验，并在排除先验时增加到$69.22^{+0.67}_{-0.86}$ km $\textrm{s}^{-1}\textrm{Mpc}^{-1}$。TPM模型相对于$Λ$ CDM通过具有$H_0$先验的$Δχ^2 = -23.72$和不具有先验的$Δχ^2 = -4.8$来改进$χ^2$。该模型允许$H_0 > 70$ km $\textrm{s}^{-1}\textrm{Mpc}^{-1}$和$S_8 < 0.80$同时具有较低的$S_8$值，这是由于物质密度$Ω_m$的降低抵消了$H_0$相对于$Λ$ CDM的增加。虽然这是一个特殊的修正引力模型，但研究修正引力的其他变体可能是解决宇宙学张力的有效途径，同时避免了对宇宙学常数的需要。

英文摘要：

We study a step-like transition in the value of the effective Planck mass (or effective gravitational constant) on cosmological scales prior to recombination. We employ CMB, BAO, and SNIa data and find they are sufficient to strongly constrain our implementation of the Effective Field Theory of Dark Energy and Modified Gravity, used to model the transition, to a limited parameter space. The data prefer a $\sim 5\%$ shift in the value of the effective Planck mass ($<10 \%$ at $2 σ$) prior to recombination. This Transitional Planck Mass (TPM) model is free to undergo its transition at any point over multiple decades of scale factor prior to recombination, $\log_{10}(a) = -5.32^{+0.96}_{-0.72}$ (68\% CL). This lowers the sound horizon at last scattering, which increases the Hubble constant to $71.09 \pm 0.75$ km $\textrm{s}^{-1}\textrm{Mpc}^{-1}$ with a combination of local measurements as prior and to $69.22^{+0.67}_{-0.86}$ km $\textrm{s}^{-1}\textrm{Mpc}^{-1}$ when the prior is excluded. The TPM model improves $χ^2$ with respect to $Λ$CDM by $Δχ^2 = -23.72$ with the $H_0$ prior and $Δχ^2 = -4.8$ without the prior. The model allows for both $H_0 > 70$ km$\textrm{s}^{-1}\textrm{Mpc}^{-1}$ and $S_8 < 0.80$ simultaneously with lower values of $S_8$ due to a reduction in the matter density $Ω_m$ to offset the increase in $H_0$ relative to $Λ$CDM. While this is a particular modified gravity model, studying other variants of modified gravity may be a productive path for potentially resolving cosmological tensions, while avoiding the need for a cosmological constant.

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