论文标题
二次仪重力中的扭转暗能
Torsional dark energy in quadratic gauge gravity
论文作者
论文摘要
重量的协变量量规理论(CCGG)是重力的量规场公式,先验性包括非金属性和扭转。它扩展了爱因斯坦(Einstein)的一般相对性理论,它至少在riemann-cartan张量中的术语。本文研究了公制兼容CCGG对宇宙学量表的含义。对于完全抗对称的扭转张量,我们在Friedmann-Lema-Robertson-Walker(FLRW)宇宙中得出所得的运动方程。在消失的二次riemann-cartan项的限制中,弗里德曼方程的修改被证明与空间曲率相当。此外,在宇宙历史的早期和后期,对经过修改的弗里德曼方程式进行了详细研究。已经证明,除了标准$λ$ CDM的行为外,还存在新颖的时间依赖性,由于扭转的存在和二次riemann-cartan术语而出现。最后,在后期,我们介绍了如何将宇宙的加速扩展理解为时空通过扭转的几何效应,从而引入了宇宙常数冗余。在这种情况下,可以计算出假定的重力汉密尔顿/拉格朗日的参数的期望值,并在物质真空能量上提供下限。
The Covariant Canonical Gauge theory of Gravity (CCGG) is a gauge field formulation of gravity which a priori includes non-metricity and torsion. It extends the Lagrangian of Einstein's theory of general relativity by terms at least quadratic in the Riemann-Cartan tensor. This paper investigates the implications of metric compatible CCGG on cosmological scales. For a totally anti-symmetric torsion tensor we derive the resulting equations of motion in a Friedmann-Lemaître-Robertson-Walker (FLRW) Universe. In the limit of a vanishing quadratic Riemann-Cartan term, the arising modifications of the Friedmann equations are shown to be equivalent to spatial curvature. Furthermore, the modified Friedmann equations are investigated in detail in the early and late times of the Universe's history. It is demonstrated that in addition to the standard $Λ$CDM behaviour of the scale factor, there exist novel time dependencies, emerging due to the presence of torsion and the quadratic Riemann-Cartan term. Finally, at late times, we present how the accelerated expansion of the Universe can be understood as a geometric effect of spacetime through torsion, rendering the introduction of a cosmological constant redundant. In such a scenario it is possible to compute an expected value for the parameters of the postulated gravitational Hamiltonian/Lagrangian and to provide a lower bound on the vacuum energy of matter.