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A hallmark of non-perturbative theories of quantum gravity is the absence of a fixed background geometry, and therefore the absence in a Planckian regime of any notion of length or scale that is defined a priori. This has potentially…

High Energy Physics - Theory · Physics 2020-02-06 J. Ambjorn , J. Gizbert-Studnicki , A. Goerlich , J. Jurkiewicz , R. Loll

In linearized quantum gravity, a shift of the average energy-momentum can be compensated by a shift of the average gravitational field. This allows a renormalization scheme that naturally removes the contribution of quantum vacuum…

General Relativity and Quantum Cosmology · Physics 2007-08-28 H. Nikolic

The idea of "asymptotically free" gravity is implemented using a constrained mimetic scalar field. The effective gravitational constant is assumed to vanish at some limiting curvature. As a result singularities in contracting spatially flat…

High Energy Physics - Theory · Physics 2020-08-05 Ali H. Chamseddine , Viatcheslav Mukhanov , Tobias Russ

We discuss the effect of wave function renormalization (WFR) in asymptotically safe gravity. We show that there are two WFR-invariant quantities, and the renormalization (RG) equations may be written entirely in terms of these quantities.…

High Energy Physics - Theory · Physics 2025-02-04 Hikaru Kawai , Nobuyoshi Ohta

We study the conformally reduced $R+R^2$ theory of gravity and we show that the theory is asymptotically safe with an ultraviolet critical manifold of dimension three. In particular, we discuss the universality properties of the fixed point…

High Energy Physics - Theory · Physics 2023-07-26 Alfio Maurizio Bonanno , Maria Conti , Sergio Luigi Cacciatori

Gravity is perturbatively renormalizable for the physical states which can be conveniently defined via foliation-based quantization. In recent sequels, one-loop analysis was explicitly carried out for Einstein-scalar and Einstein-Maxwell…

High Energy Physics - Theory · Physics 2021-11-12 I. Y. Park

We discover that chiral symmetry does not act as an infrared attractor of the renormalization group flow under the impact of quantum gravity fluctuations. Thus, observationally viable quantum gravity models must respect chiral symmetry. In…

General Relativity and Quantum Cosmology · Physics 2017-02-08 Astrid Eichhorn , Stefan Lippoldt

Asymptotic Safety is a promising framework towards the understanding, in a non-perturbative way, of Quantum Gravity. It treats the Newton's constant G_N and the cosmological constant \Lambda as running coupling of an effective action. At…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-17 Vasilios Zarikas

Asymptotic safety describes a scenario in which general relativity can be quantized as a conventional field theory, despite being nonrenormalizable when expanding it around a fixed background geometry. It is formulated in the framework of…

High Energy Physics - Theory · Physics 2013-02-06 J. Ambjorn , A. Goerlich , J. Jurkiewicz , R. Loll

Asymptotic Safety (AS) Paradigm is an interesting set of ideas and methods towards a meaningful quantization of Gravity. A brief review of phenomenological consequences in the context of AS regarding cosmology with emphasis on dark energy…

General Relativity and Quantum Cosmology · Physics 2024-10-11 Vasilios Zarikas

We derive quantum gravity contributions to the beta functions of the gauge and Yukawa couplings of a matter theory using the Schwinger proper-time flow equation. Working in the Einstein-Hilbert truncation, we investigate the gauge-fixing…

High Energy Physics - Phenomenology · Physics 2026-04-06 Gabriele Giacometti , Kamila Kowalska , Daniele Rizzo , Enrico Maria Sessolo , Dario Zappala

In this talk, I present a theory of quantum gravity beyond Einstein. The theory is established based on spinnic and scaling gauge symmetries by treating the gravitational force on the same footing as the electroweak and strong forces. A…

High Energy Physics - Theory · Physics 2015-11-04 Yue-Liang Wu

The gravitational asymptotic safety program envisions a high-energy completion of gravity based on a non-Gaussian renormalization group fixed point. A key step in this program is the transition from Euclidean to Lorentzian signature…

High Energy Physics - Theory · Physics 2023-06-21 Frank Saueressig , Jian Wang

Over the last years the Asymptotic Safety program has matured into a serious candidate for a quantum theory of gravity compatible with observations. The rapid technical progress in computing renormalisation group flows for gravity and…

High Energy Physics - Theory · Physics 2020-01-08 Benjamin Knorr , Chris Ripken , Frank Saueressig

In a series of recent works based on foliation-based quantization in which renormalizability has been achieved for the physical sector of the theory, we have shown that the use of the standard graviton propagator interferes, due to the…

High Energy Physics - Theory · Physics 2020-12-15 I. Y. Park

We derive the flow equation for the gravitational effective average action in an $f(R)$ truncation on hyperbolic spacetimes using the exponential parametrization of the metric. In contrast to previous works on compact spaces, we are able to…

High Energy Physics - Theory · Physics 2016-10-12 Kevin Falls , Nobuyoshi Ohta

We study fixed points of quantum gravity with renormalisation group methods, and a procedure to remove convergence-limiting poles from the flow. The setup is tested within the $f(R)$ approximation for gravity by solving exact recursive…

General Relativity and Quantum Cosmology · Physics 2019-07-03 Kevin G. Falls , Daniel F. Litim , Jan Schröder

A new approach to quantum gravity is presented based on a nonlinear quantization scheme for canonical field theories with an implicitly defined Hamiltonian. The constant mean curvature foliation is employed to eliminate the momentum…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Charles H-T Wang

A scale--dependent effective action for gravity is introduced and an exact nonperturbative evolution equation is derived which governs its renormalization group flow. It is invariant under general coordinate transformations and satisfies…

High Energy Physics - Theory · Physics 2009-10-30 M. Reuter

The framework of trans-Planckian asymptotic safety has been shown to generate phenomenological predictions in the Standard Model and in some of its simple new physics extensions. A heuristic approach is often adopted, which bypasses the…

High Energy Physics - Phenomenology · Physics 2023-08-08 Wojciech Kotlarski , Kamila Kowalska , Daniele Rizzo , Enrico Maria Sessolo