标题： Λ在渐近安全框架下的重求和量子引力中的估计 显示英文标题

标题： An Estimate of Λin Resummed Quantum Gravity in the Context of Asymptotic Safety

摘要： 我们表明，通过使用最近发展的精确重求和技术，这些技术基于将Yennie、Frautschi和Suura的方法扩展到Feynman对Einstein理论的表述，我们得到了Weinberg所提出的无量纲引力常数和宇宙学常数的紫外固定点行为的量子场论描述。 将我们的工作与Bonanno和Reuter对普朗克尺度宇宙学的相关现象学渐近安全性分析联系起来，我们估计了宇宙学常数\Lambda 的值。 我们找到令人鼓舞的估计\rho _\Lambda \equiv \frac{\Lambda}{8\pi G_N} \simeq (2.4\times 10^{-3}eV)^4. 虽然这个数值接近最近的实验观测结果，但我们提醒读者，该估计涉及许多仍存在显著不确定性的模型参数，例如普朗克尺度宇宙学时期与弗里德曼-罗伯逊-沃尔克辐射主导时期之间的过渡时间值，目前我们的理解允许其不确定性至少有两个数量级，这将使我们对\rho _\Lambda 的估计改变至少四个数量级。 我们也将讨论此类理论不确定性。 我们解释了为什么在我们对\rho _\Lambda 的估计方法中，大统一理论和电弱尺度的真空能量会受到抑制。 作为额外的收获，我们展示了我们的估计如何对超对称大统一理论进行约束。 显示英文摘要

摘要： We show that, by using recently developed exact resummation techniques based on the extension of the methods of Yennie, Frautschi and Suura to Feynman's formulation of Einstein's theory, we get quantum field theoretic descriptions for the UV fixed-point behaviors of the dimensionless gravitational and cosmological constants postulated by Weinberg. Connecting our work to the attendant phenomenological asymptotic safety analysis of Planck scale cosmology by Bonanno and Reuter, we estimate the value of the cosmological constant \Lambda. We find the encouraging estimate \rho_\Lambda\equiv \frac{\Lambda}{8\pi G_N} \simeq (2.4\times 10^{-3}eV)^4. While this numerical value is close to recent experimental observations, we caution the reader that the estimate involves a number of model parameters that still possess significant levels of uncertainty, such as the value of the transition time between the Planck scale cosmology era and the Friedmann-Robertson-Walker radiation dominated era, where our current understanding allows for at least two orders of magnitude in its uncertainty and this would change our estimate of \rho_\Lambda by at least four orders of magnitude. We discuss such theoretical uncertainties as well. We show why GUT and EW scale vacuum energies from spontaneous symmetry breaking are suppressed in our approach to the estimation of \rho_\Lambda. As a bonus, we show how our estimate constrains susy GUTS.