Is Quantum Einstein Gravity Nonperturbatively Renormalizable?

TL;DR

This paper provides evidence that four-dimensional Quantum Einstein Gravity may be nonperturbatively renormalizable through asymptotic safety, suggesting it could be a consistent fundamental theory at all scales.

Contribution

It demonstrates the existence of a non-Gaussian fixed point in a truncated flow equation, supporting the asymptotic safety scenario for Quantum Einstein Gravity.

Findings

Existence of a suitable non-Gaussian fixed point.

Supports the asymptotic safety conjecture.

Truncation includes Einstein-Hilbert and higher derivative terms.

Abstract

We find considerable evidence supporting the conjecture that four-dimensional Quantum Einstein Gravity is ``asymptotically safe'' in Weinberg's sense. This would mean that the theory is likely to be nonperturbatively renormalizable and thus could be considered a fundamental (rather than merely effective) theory which is mathematically consistent and predictive down to arbitrarily small length scales. For a truncated version of the exact flow equation of the effective average action we establish the existence of a non-Gaussian renormalization group fixed point which is suitable for the construction of a nonperturbative infinite cutoff-limit. The truncation ansatz includes the Einstein-Hilbert action and a higher derivative term.