Quantum Einstein gravity

  title={Quantum Einstein gravity},
  author={Martin Reuter and Frank Saueressig},
  journal={New Journal of Physics},
We give a pedagogical introduction to the basic ideas and concepts of the Asymptotic Safety program in quantum Einstein gravity. Using the continuum approach based upon the effective average action, we summarize the state of the art of the field with a focus on the evidence supporting the existence of the non-trivial renormalization group fixed point at the heart of the construction. As an application, the multifractal structure of the emerging space-times is discussed in detail. In particular… 

The continuum limit of loop quantum gravity - a framework for solving the theory

The construction of a continuum limit for the dynamics of loop quantum gravity is unavoidable to complete the theory. We explain that such a construction is equivalent to obtaining the continuum

Effective universality in quantum gravity

We investigate the asymptotic safety scenario for a scalar-gravity system. This system contains two avatars of the dynamical Newton coupling, a gravitational self-coupling and a scalar-graviton


We discuss the conceptual ideas underlying the Asymptotic Safety approach to the nonperturbative renormalization of gravity. By now numerous functional renormalization group (RG) studies predict the

Quantum Spacetime and the Renormalization Group: Progress and Visions

The quest for a consistent theory which describes the quantum microstructure of spacetime seems to require some departure from the paradigms that have been followed in the construction of quantum

Quantum Gravity from Fundamental Questions to Phenomenological Applications

Investigating quantum gravity requires a comprehension of both, general relativity and quantum field theory. Therefore this thesis starts, after a general introduction to the treated topics, with a

Resolving Spacetime Singularities within Asymptotic Safety.

This work compute the nonperturbative momentum dependence of a specific structure function within the gravitational asymptotic safety program which encodes the quantum corrections to the graviton propagator for momenta above the Planck scale, thereby removing the classical singularity.

From Renormalization Group Flows to Cosmology

According to the asymptotic-safety conjecture, the gravitational renormalization group flow features an ultraviolet-attractive fixed point that makes the theory renormalizable and ultraviolet

Is There a C-Function in 4D Quantum Einstein Gravity?

We describe a functional renormalization group-based method to search for ‘C-like’ functions with properties similar to that in 2D conformal field theory. It exploits the mode counting properties of

Towards Reconstructing the Quantum Effective Action of Gravity.

This work applies the matching-template formalism to the autocorrelation function of spatial volume fluctuations measured within the causal dynamical triangulations program, suggesting that the corresponding quantum effective action consists of the Einstein-Hilbert action supplemented by a nonlocal interaction term.

Quantum Gravity: A Fluctuating Point of View

In this contribution, we discuss the asymptotic safety scenario for quantum gravity with a functional renormalization group approach that disentangles dynamical metric fluctuations from the



The role of background independence for asymptotic safety in Quantum Einstein Gravity

We discuss various basic conceptual issues related to coarse graining flows in quantum gravity. In particular, the requirement of background independence is shown to lead to renormalization group

A fixed point for truncated quantum Einstein gravity

A perturbative quantum theory of the two Killing vector reduction of Einstein gravity is constructed. Although the reduced theory inherits from the full one the lack of standard perturbative

Evidence for asymptotic safety from lattice quantum gravity.

The spectral dimension for nonperturbative quantum gravity defined via Euclidean dynamical triangulations is calculated and it is argued that the short-distance value of 3/2 for the spectral dimension may resolve the tension between asymptotic safety and the holographic principle.

Asymptotically free scalar curvature-ghost coupling in quantum Einstein gravity

We consider the asymptotic-safety scenario for quantum gravity which constructs a nonperturbatively renormalizable quantum gravity theory with the help of the functional renormalization group (RG).

Asymptotically safe Lorentzian gravity.

Surprisingly, the two fixed points have strikingly similar characteristics, suggesting that Euclidean and Lorentzian quantum gravity belong to the same universality class at high energies.

Lectures on Non-Perturbative Canonical Gravity

Notes prepared in Collaboration with Ranjeet S Tate It is now generally recognized that perturbative field theoretical methods that have been highly successful in the quantum description of

Ultraviolet fixed point and generalized flow equation of quantum gravity

A new exact renormalization group equation for the effective average action of Euclidean quantum gravity is constructed. It is formulated in terms of the component fields appearing in the