Asymptotic safety in gravity and sigma models

Asymptotic safety and Kaluza-Klein gravitons at the LHC

We study Drell-Yan production at the LHC in low-scale quantum gravity models with extra dimensions. Asymptotic safety implies that the ultraviolet behavior of gravity is dictated by a fixed point. We show how the energy dependence of Newton’s coupling regularizes the gravitational amplitude using a renormalization group improvement. We study LHC predictions and find that Kaluza-Klein graviton s...

Asymptotic Optimality of Nonparametric Tests for Restricted Alternatives in Multivariate Mixed Models

Dilatonic gravity near two dimensions and asymptotic freedom of the gravitational coupling constant

Two models of dilatonic gravity are investigated: (i) dilaton-Yang-Mills gravity and (ii) higher-derivative dilatonic gravity. Both are renormalizable in 2 + ǫ dimensions and have a smooth limit for ǫ → 0. The corresponding one-loop effective actions and beta-functions are found. Both theories are shown to possess a non-trivial ultraviolet fixed point —for all dilatonic couplings— in which the ...

Asymptotic Safety

Asymptotic safety is a set of conditions, based on the existence of a nontrivial fixed point for the renormalization group flow, which would make a quantum field theory consistent up to arbitrarily high energies. After introducing the basic ideas of this approach, I review the present evidence in favor of an asymptotically safe quantum field theory of gravity. To appear in “ Approaches to Quant...

Dilaton Gravity, Poisson Sigma Models and Loop Quantum Gravity

Spherically symmetric gravity in Ashtekar variables coupled to Yang–Mills theory in two dimensions and its relation to dilaton gravity and Poisson sigma models are discussed. After introducing its loop quantization, quantum corrections for inverse triad components are shown to provide a consistent deformation without anomalies. The relation to Poisson sigma models provides a covariant action pr...