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arXiv 1802.04281hep-thgr-qc
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共形扇形的重整化群性质：朝向微扰重整化的量子引力

Renormalization group properties of the conformal sector: towards perturbatively renormalizable quantum gravity

Tim R. Morris

备注：
52 pages, 4 figures; fixed typos; improved explanation of the sign of V, and the use of Sturm-Liouville theory. To be publ in JHEP
发表信息：
JHEP 08 (2018) 024
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摘要：

威尔逊重整化群（RG）需要欧几里得签名。度规的共形因子有一个错误符号的动力学项，这对它的RG性质有深远的影响。一般对于共形扇区，完全流动只存在于相反的方向（即从红外到紫外）。高斯不动点支持无限序列的复合本征算子增加红外相关性（越来越负的质量维度），这是正交和完整的裸相互作用，平方可积在适当的措施。这些本征算子在$\hbar$中是非微扰的，并且是瞬逝的。对于$\mathbb{R}^4$时空，每个重整化的物理算符都存在，但只在场振幅为零时才有支撑。在无限多个非零耦合的一般情况下，如果存在完整的RG流，则其在红外中的特征在于尺度$Λ_\mathrm{p}>0$，超过该尺度，场振幅被指数抑制。在长度尺度为$L$的其他时空上，一旦某种不均匀性的普适测度超过$O(1)+2πL^2Λ^2_\mathrm{p}$，流动就不复存在。对于宇宙学来说，重要的是，宇宙的最小尺寸因此与不均匀性的程度有关，而尺寸为零的时空被要求几乎是均匀的。我们开始研究这种奇异的量子场论在相互作用的水平，并讨论了完整的量子引力理论应该是什么样子，一个必须因此微扰重整化牛顿常数，但非微扰$\hbar$。

英文摘要：

The Wilsonian renormalization group (RG) requires Euclidean signature. The conformal factor of the metric then has a wrong-sign kinetic term, which has a profound effect on its RG properties. Generically for the conformal sector, complete flows exist only in the reverse direction (i.e. from the infrared to the ultraviolet). The Gaussian fixed point supports infinite sequences of composite eigenoperators of increasing infrared relevancy (increasingly negative mass dimension), which are orthonormal and complete for bare interactions that are square integrable under the appropriate measure. These eigenoperators are non-perturbative in $\hbar$ and evanescent. For $\mathbb{R}^4$ spacetime, each renormalised physical operator exists but only has support at vanishing field amplitude. In the generic case of infinitely many non-vanishing couplings, if a complete RG flow exists, it is characterised in the infrared by a scale $Λ_\mathrm{p}>0$, beyond which the field amplitude is exponentially suppressed. On other spacetimes, of length scale $L$, the flow ceases to exist once a certain universal measure of inhomogeneity exceeds $O(1)+2πL^2Λ^2_\mathrm{p}$. Importantly for cosmology, the minimum size of the universe is thus tied to the degree of inhomogeneity, with spacetimes of vanishing size being required to be almost homogeneous. We initiate a study of this exotic quantum field theory at the interacting level, and discuss what the full theory of quantum gravity should look like, one which must thus be perturbatively renormalizable in Newton's constant but non-perturbative in $\hbar$.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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