论文标题

在改良的对称触觉重力中加速宇宙的扩展

Accelerating expansion of the universe in modified symmetric teleparallel gravity

论文作者

Solanki, Raja, De, Avik, Mandal, Sanjay, Sahoo, P. K.

论文摘要

黑暗能源的基本本质和起源是理论物理学的主要奥秘之一。在一般相对论理论中,宇宙常数$λ$是对暗能量的最简单解释。另一方面,宇宙常数$λ$遭受了一个精致的问题,所谓的微调问题。这激发了人们修改爱因斯坦Gr的时空几何形状。 $ f(q)$重力是最近提出的重力理论,其中非金属标量$ q $驱动重力相互作用。在本文中,我们考虑了线性$ f(q)$模型,特别是$ f(q)=αq +β$,其中$α$和$β$是免费参数。然后,我们估计模型参数的最佳拟合值,这些值与最近的观察数据集一致。我们使用更新的$ H(Z)$数据集的57点,BAO数据集的6点以及万神殿超新星样品中的1048点。我们将贝叶斯分析和可能性功能以及马尔可夫链蒙特卡洛(MCMC)方法应用。此外,我们分析了宇宙学参数的物理行为,例如密度,减速和与模型参数约束值相对应的EOS参数。减速参数的演变预测了从减速到宇宙加速阶段的过渡。此外,状态参数方程的演变描述了暗能能流体部分的典型类型行为。我们发现,我们的$ f(q)$宇宙学模型可以有效地描述较晚的宇宙加速度,而无需调用物质部分中的任何暗能量组件。

The fundamental nature and origin of dark energy are one of the premier mysteries of theoretical physics. In General Relativity Theory, the cosmological constant $Λ$ is the simplest explanation for dark energy. On the other hand, the cosmological constant $Λ$ suffers from a delicate issue so-called fine-tuning problem. This motivates one to modify the spacetime geometry of Einstein's GR. The $f(Q)$ gravity is a recently proposed modified theory of gravity in which the non-metricity scalar $Q$ drives the gravitational interaction. In this article, we consider a linear $f(Q)$ model, specifically $f(Q)=αQ + β$, where $α$ and $β$ are free parameters. Then we estimate the best fit values of model parameters that would be in agreement with the recent observational data sets. We use 57 points of the updated $H(z)$ data sets, 6 points of the BAO data sets, and 1048 points from the Pantheon supernovae samples. We apply the Bayesian analysis and likelihood function along with the Markov Chain Monte Carlo (MCMC) method. Further, we analyse the physical behaviour of cosmological parameters such as density, deceleration, and the EoS parameters corresponding to the constraint values of the model parameters. The evolution of deceleration parameter predicts a transition from decelerated to accelerated phases of the universe. Further, the evolution of equation of state parameter depicts quintessence type behaviour of the dark energy fluid part. We found that our $f(Q)$ cosmological model can effectively describe the late time cosmic acceleration without invoking any dark energy component in the matter part.

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