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arXiv 2006.15596hep-thgr-qchep-ph
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外尔引力的阴暗面

Dark side of Weyl gravity

Petr Jizba, Lesław Rachwał, Stefano G. Giaccari, Jaroslav Kňap

摘要:

利用泛函重整化群,从假设为高斯的UV不动点出发,研究了量子Weyl引力标度不变性的动力学破坏.为此,我们求助于两类巴赫平坦的背景,即最大对称时空和Ricci平坦的背景中的改进的单圈计划。我们发现,除了一个真正的IR固定点,是在零值的运行规模达到,重整化群流也表现出弹跳行为。我们证明了所发现的IR不动点在所考虑的耦合空间中是IR稳定的。作为下一步,我们分析物理学在破碎阶段。特别是,我们表明,在低能量部门的破碎阶段,该理论看起来像Starobinsky $f(R)$重力与重力-宇宙学常数,有一个负号相比,通常的物质诱导的宇宙学常数。我们讨论宇宙暴胀的影响,并强调Starobinsky的参数和引力宇宙学常数之间的非平凡的关系。文中还讨论了红外不动点的方案独立性和迹异常的作用等问题。

英文摘要:

With the help of a functional renormalization group, we study the dynamical breakdown of scale invariance in quantum Weyl gravity by starting from the UV fixed point that we assume to be Gaussian. To this end, we resort to two classes of Bach-flat backgrounds, namely maximally symmetric spacetimes and Ricci-flat backgrounds in the improved one-loop scheme. We show that apart from a genuine IR fixed point that is reached at a zero value of the running scale, the renormalization group flow also exhibits bouncing behavior. We demonstrate that the IR fixed point found is IR-stable in the space of the considered couplings. As a next step, we analyze physics in the broken phase. In particular, we show that in the low-energy sector of the broken phase, the theory looks like Starobinsky $f(R)$ gravity with a gravi-cosmological constant that has a negative sign in comparison to the usual matter-induced cosmological constant. We discuss implications for cosmic inflation and highlight a non-trivial relation between Starobinsky's parameter and the gravi-cosmological constant. Salient issues, including the scheme independence of the IR fixed point and the role of trace anomaly, are also discussed.

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