发表机构
University of Catania; INFN, Sezione di Catania（卡塔尼亚大学; 意大利国家核物理研究所卡塔尼亚分部）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究提出引力量子涨落导致宇宙学常数被红外尺度屏蔽，在爱因斯坦-希尔伯特+$R^2$截断下，运行常数趋于普适标度$\Lambda_k\sim k^2$，最终在哈勃尺度达到观测值。
AI 中文摘要
观测到的宇宙学常数由当前宇宙最深处的红外尺度设定，而非由贡献于真空能的微观尺度设定。我们表明，随着引力场的量子涨落被逐步考虑，这一现象自然涌现。考虑爱因斯坦-希尔伯特+$R^2$截断的引力理论，我们发现，在参数空间的广阔区域内，理论会发展出不稳定性，这些不稳定性产生大幅度的量子涨落，并主导重整化群流。一旦流进入该区域，它便一直保持在那里直至红外端，并逐渐失去对其边界条件的记忆。运行中的宇宙学常数$\Lambda_k$（$k$为运行尺度）被驱动向普适的红外标度行为$\Lambda_k\sim \lambda_{_{\rm IR}}\\,k^2$，其中$\lambda_{_{\rm IR}}= \frac{1}{2(\pi-2)}$。在最深红外尺度$k\sim H_0$（当前哈勃尺度）处，宇宙学常数随即被屏蔽至其观测值$\Lambda_{_{\rm IR}}\sim H_0^2$。
英文摘要
The observed cosmological constant is set by the deepest infrared scale of the present universe rather than by the microscopic scales that contribute to the vacuum energy. We show that this emerges as the quantum fluctuations of the gravitational field are progressively taken into account. Considering the Einstein-Hilbert+$R^2$ truncation of gravity, we find that in a wide region of the parameter space the theory develops instabilities that give rise to large amplitude quantum fluctuations which govern the renormalization group flow. Once the flow enters this region, it remains there all the way towards the infrared and progressively loses memory of its boundary conditions. The running cosmological constant $Λ_k$ ($k$ is the running scale) is driven towards the universal infrared scaling $Λ_k\sim λ_{_{\rm IR}}\,k^2$, with $λ_{_{\rm IR}}= \frac{1}{2(π-2)}$. At the deepest infrared scale $k_{_{\rm IR}}\sim H_0$ (the current Hubble scale), the cosmological constant is then screened to its observed value $Λ_{_{\rm IR}}\sim H_0^2$.
Comments6 pages, 2 figures + Supplemental Material (8 pages). Slight modifications in the notation; acknowledgments added
