论文标题
具有诱导轴向模式和幻影屏障交叉的模拟物质转化
Mimetic-Metric-Torsion with induced Axial mode and Phantom barrier crossing
论文作者
论文摘要
我们扩展了模拟物质重力理论的基本形式主义，以一种模拟标量场可以在几何上表现为不仅是扭转痕量模式的来源，而且还可以表现出其轴向（或伪痕迹）模式的来源。具体而言，我们认为模拟场是（i）与Riemann-Cartan作用的众所周知的Holst延伸明确耦合，并且（ii）与相关的Barbero-Immirzi场的平方识别，这被认为是伪级。该理论中最初普遍存在的同伴对称性仍然存在，因为相关的cartan变换不会影响扭转伪痕迹，因此也会影响霍尔斯特术语。要求理论保留空间平价对称性，我们专注于宇宙学黑暗部门的几何统一，并表明在宇宙发展过程中，超级加速度的制度始终是可行的。从观察的角度来看，假设宇宙学的演变曲线非常接近$ $ cdm，我们进一步表明，在低红移下，所谓的幻影屏障可能会平稳，但是对于非常有限的参数域而言。随后通过检查相关扭转参数的演变来确定超级加速度的程度。
We extend the basic formalism of mimetic-metric-torsion gravity theory, in a way that the mimetic scalar field can manifest itself geometrically as the source of not only the trace mode of torsion, but also its axial (or, pseudo-trace) mode. Specifically, we consider the mimetic field to be (i) coupled explicitly to the well-known Holst extension of the Riemann-Cartan action, and (ii) identified with the square of the associated Barbero-Immirzi field, which is presumed to be a pseudo-scalar. The conformal symmetry originally prevalent in the theory would still hold, as the associated Cartan transformations do not affect the torsion pseudo-trace, and hence the Holst term. Demanding the theory to preserve the spatial parity symmetry as well, we focus on a geometric unification of the cosmological dark sector, and show that a super-accelerating regime in the course of evolution of the universe is always feasible. From the observational perspective, assuming the cosmological evolution profile to be very close to that for $Ł$CDM, we further show that there could be a smooth crossing of the so-called phantom barrier at a low red-shift, however for a very restricted parametric domain. The extent of the super-acceleration have subsequently been ascertained by examining the evolution of the relevant torsion parameters.
