论文标题
暂时变化的通用引力“恒定”和能量动量平方重力的光速
Temporally Varying Universal Gravitational "Constant" and Speed of Light in Energy Momentum Squared Gravity
论文作者
论文摘要
能量动量平方重力(EMSG)是一个宇宙学模型,其中比例因子始终不消失,因此不偏爱大爆炸宇宙学。但是,辐射统治宇宙中密度的曲线表明,EMSG支持通货膨胀宇宙学。通货膨胀的宇宙学模型成功地为诸如地平线问题,平坦性问题和宇宙恒定的少量价值(迄今为止尚无通货膨胀模型)提供了令人信服的答案。因此,引入了不同的光速(VSL),这些速度是一类宇宙学模型,它不利于通货膨胀,并提出了一种替代途径来解决这些宇宙学问题,只需允许光速(和牛顿引力常数)变化。 VSL理论的动机是解决通货膨胀的缺点,但并未解决与最初的大爆炸奇点有关的缺点。本着这种精神,我们在这里展示了一种新颖的宇宙学模型,它通过在EMSG的框架中融合了相互不同的速度$ c(t)$和牛顿重力常数$ g(t)$,从而摆脱了“最初的大爆炸奇点”和“通货膨胀”。我们报告说,在EMSG中,对于灰尘宇宙($ω= 0 $),宇宙学模型在$ c(t)$和$ g(t)$和$ g(t)$和常数$ c $和$ g $的宇宙学模型是无法区分的,而对于辐射主导的宇宙,$ω= 1/3 $($ω= 1/3 $),与$ c($ c($ c)相互作用的$ c(t)$ c(t)$ c(t)$ c(t)$ c(t)$ c(t)$ c(t)$ c(t)没有最初的大爆炸奇点。我们进一步报告说,对于代表弹跳宇宙学模型的规模因子的ANSATZ,可以将VSL理论应用于二次$ t $重力模型,以摆脱“通货膨胀”和“大爆炸奇点”,并同时解决上述宇宙学谜团。
Energy Momentum Squared Gravity (EMSG) is a cosmological model where the scale factor is non vanishing at all times and hence does not favor big bang cosmology. However, the profile of density in the radiation dominated universe shows that EMSG supports inflationary cosmology. Inflationary cosmological models are successful in providing convincing answers to major cosmological issues like horizon problem, flatness problem and small value of cosmological constant but hitherto no model of inflation has been observationally confirmed. Owing to this, Varying Speed of Light (VSL) were introduced which are a class of cosmological models which disfavor inflation and propose an alternative route to solve these cosmological issues by just allowing the speed of light (and Newtonian Gravitational constant) to vary. VSL theories were motivated to address the shortcomings of inflation but do not address the shortcomings related to the initial big bang singularity. In this spirit, we present here a novel cosmological model which is free from both the "initial big bang singularity" and "inflation" by incorporating a mutually varying speed of light $c(t)$ and Newtonian gravitational constant $G(t)$ in the framework of EMSG. We report that in EMSG, for a dust universe ($ω=0$), cosmological models for a time varying $c(t)$ and $G(t)$ and constant $c$ and $G$ are indistinguishable, whereas for a radiation dominated universe ($ω= 1/3$), a mutually varying $c(t)$ and $G(t)$ provides an exiting alternative to inflationary cosmology which is also free from initial big bang singularity. We further report that for an ansatz of scale factor representing a bouncing cosmological model, the VSL theory can be applied to a quadratic $T$ gravity model to get rid of "inflation" and "big bang singularity" and concurrently solve the above mentioned cosmological enigmas.