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arXiv 2106.03093astro-ph.COgr-qc
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由于引力和哈勃张力的一般修正引起的后期加速

Late time acceleration due to generic modification of gravity and Hubble tension

Shahnawaz A. Adil, Mayukh R. Gangopadhyay, M. Sami, Mohit K. Sharma

摘要:

我们考虑的情况下,修改的重力,这是通用的晚时间加速度,即,在约旦框架的加速度和爱因斯坦框架中没有加速度。这种可能性是通过假设暗物质和重子组成部分之间的相互作用,在爱因斯坦框架中,这是通过去约旦框架使用非正式的变换,产生一个外来的有效流体负责造成幻影穿越在晚些时候删除。在这种情况下,过去的演变是没有区别于$Λ$ CDM,但晚时间的动力学是一般不同的,由于幻影交叉的存在,导致单调增加的膨胀率,从而产生独特的晚时间的宇宙特征。后者在解决哈勃参数的CMB(宇宙微波背景)测量值与当地观测值之间的矛盾中起着至关重要的作用。我们表明,哈勃紧张显着减少在所选择的比例因子参数化的情况下考虑。模型中宇宙年龄的估计值在低红移和高红移区域的观测范围内。

英文摘要:

We consider a scenario of modified gravity, which is generic to late-time acceleration, namely, acceleration in the Jordan frame and no acceleration in the Einstein frame. The possibility is realized by assuming an interaction between dark matter and the baryonic component in the Einstein frame which is removed by going to the Jordan frame using a disformal transformation giving rise to an exotic effective fluid responsible for causing phantom crossing at late times. In this scenario, past evolution is not distinguished from $Λ$CDM but late time dynamics is generically different due to the presence of phantom crossing that causes a monotonous increase in the expansion rate giving rise to distinctive late-time cosmic feature. The latter can play a crucial role in addressing the tension between the observed value of Hubble parameter by CMB (Cosmic Microwave Background) measurements and the local observations. We demonstrate that the Hubble tension significantly reduces in the scenario under consideration for the chosen scale factor parametrizations. The estimated age of the universe in the model is well within the observational bounds in the low and high red-shift regimes.

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