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We explore the possibility of a consistent cosmology based on the gauge-fixing independent running of the gravitational and cosmological constants ($G$ and $\Lambda$) in the framework of effective quantum gravity. In particular, their…

General Relativity and Quantum Cosmology · Physics 2024-04-30 Nicolas R. Bertini , Davi C. Rodrigues , Ilya L. Shapiro

We apply the new quantization scheme outlined in Phys. Rev. D102 (2020) 125001 to explore the influence which quantum vacuum fluctuations of the spacetime metric exert on the universes of Quantum Einstein Gravity, which is regarded an…

High Energy Physics - Theory · Physics 2021-12-22 Maximilian Becker , Martin Reuter

We analyze the perturbative implications of the most general high derivative approach to quantum gravity based on a diffeomorphism invariant local action. In particular, we consider the super-renormalizable case with a large number of…

High Energy Physics - Theory · Physics 2009-10-30 M. Asorey , J. L. López , I. L. Shapiro

I review here some motivations to consider a theory of gravity based on independent metric and connection, and its status as a quantum theory.

General Relativity and Quantum Cosmology · Physics 2020-03-24 Roberto Percacci

We summarize recent evidence supporting the conjecture that four-dimensional Quantum Einstein Gravity (QEG) is nonperturbatively renormalizable along the lines of Weinberg's asymptotic safety scenario. This would mean that QEG is…

High Energy Physics - Theory · Physics 2009-11-07 O. Lauscher , M. Reuter

Recently a scale invariant theory of gravity was constructed by imposing a conformal symmetry on general relativity. The imposition of this symmetry changed the configuration space from superspace - the space of all Riemannian 3-metrics…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Bryan Kelleher

Quantum electrodynamics describes the interactions of electrons and photons. Electric charge (the gauge coupling constant) is energy dependent, and there is a previous claim that charge is affected by gravity (described by general…

High Energy Physics - Theory · Physics 2011-11-10 David J. Toms

We construct a family of measures for random fields based on the iterated subdivision of simple geometric shapes (triangles, squares, tetrahedrons) into a finite number of similar shapes. The intent is to construct continuum limits of scale…

High Energy Physics - Theory · Physics 2012-07-05 Arnab Kar , S. G. Rajeev

Recently\cite{BQG}, it was shown that quantum effects of matter could be identified with the conformal degree of freedom of the space-time metric. Accordingly, one can introduce quantum effects either by making a scale transformation (i.e.…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Fatimah Shojai , Ali Shojai , Mehdi Golshani

We investigate the structure of equations of motion and lagrangian constraints in a general theory of massive spin 2 field interacting with external gravity. We demonstrate how consistency with the flat limit can be achieved in a number of…

High Energy Physics - Theory · Physics 2008-11-26 I. L. Buchbinder , D. M. Gitman , V. D. Pershin

A possible way to capture the effects of quantum gravity in spacetime at a mesoscopic scale, for relatively low energies, is through an energy dependent metric, such that particles with different energies probe different spacetimes. In this…

General Relativity and Quantum Cosmology · Physics 2022-10-12 G. Chirco , S. Liberati , J. J. Relancio

We propose fundamental scale invariance as a new theoretical principle beyond renormalizability. Quantum field theories with fundamental scale invariance admit a scale-free formulation of the functional integral and effective action in…

High Energy Physics - Theory · Physics 2021-02-24 C. Wetterich

Scaling solutions for the effective action in dilaton quantum gravity are investigated within the functional renormalization group approach. We find numerical solutions that connect ultraviolet and infrared fixed points as the ratio between…

High Energy Physics - Theory · Physics 2017-02-01 Tobias Henz , Jan Martin Pawlowski , Christof Wetterich

After short historical overview we describe the difficulties with application of standard QFT methods in quantum gravity (QG). The incompatibility of QG with the use of classical continuous space-time required conceptually new approach. We…

High Energy Physics - Theory · Physics 2014-12-01 Jerzy Lukierski

We consider functional-integral quantisation of the moduli of all quantum metrics defined as square-lengths $a$ on the edges of a Lorentzian square graph. We determine correlation functions and find a fixed relative uncertainty $\Delta…

General Relativity and Quantum Cosmology · Physics 2020-01-08 Shahn Majid

Using the background-metric independence for the traceless mode as well as the conformal mode, 4D quantum gravity is described as a quantum field theory defined on a non-dynamical background-metric. The measure then induces an action with 4…

High Energy Physics - Theory · Physics 2009-10-31 Ken-ji Hamada , Fumihiko Sugino

We examine the question of scale vs. conformal invariance for the linearized Einstein-Hilbert action, which describes the IR fixed point of quantum gravity. In $D = 4$, although the action is not conformally invariant in the usual sense, we…

High Energy Physics - Theory · Physics 2022-04-21 Kara Farnsworth , Kurt Hinterbichler , Ondrej Hulik

This paper presents a framework for Quantum causal modeling based on the interpretation of causality as a relation between an observer's probability assignments to hypothetical or counterfactual experiments. The framework is based on the…

Quantum Physics · Physics 2020-01-15 Jacques Pienaar

The consequences of considering the measure of integration in the action to be defined by degrees of freedom independent of the metric are studied. Models without the cosmological constant problem, new ways of spontaneously breaking scale…

High Energy Physics - Theory · Physics 2007-05-23 E. I. Guendelman

The issue of the physical equivalence between the different coordinate system in Einstein theory is revised. Gauge fixing influences results of measurements and physics are different in two different coordinate system. Spacetime metric…

General Physics · Physics 2012-12-27 Sergey M. Kozyrev , Rinat A. Daishev