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Recently, it is shown that, the quantum effects of matter are well described by the conformal degree of freedom of the space-time metric. On the other hand, it is a wellknown fact that according to Einstein's gravity theory, gravity and…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Ali Shojai

Quantum theory of conformal factor coupled with matter fields is investigated. The more simple case of the purely classical scalar matter is considered. It is calculated the conformal factor contribution to the effective potential of scalar…

High Energy Physics - Theory · Physics 2009-10-28 I. L. Shapiro

Conformal loop quantum gravity provides an approach to loop quantization through an underlying conformal structure i.e. conformally equivalent class of metrics. The property that general relativity itself has no conformal invariance is…

General Relativity and Quantum Cosmology · Physics 2017-10-06 Olivier J. Veraguth , Charles H. -T. Wang

The most general version of a renormalizable $d=4$ theory corresponding to a dimensionless higher-derivative scalar field model in curved spacetime is explored. The classical action of the theory contains $12$ independent functions, which…

High Energy Physics - Theory · Physics 2010-04-06 E. Elizalde , A. G. Jacksenaev , S. D. Odintsov , I. L. Shapiro

A low-energy perturbation theory is developed from the nonperturbative framework of covariant Loop Quantum Gravity (LQG) by employing the background field method. The resulting perturbation theory is a 2-parameter expansion in the…

General Relativity and Quantum Cosmology · Physics 2014-06-17 Muxin Han

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 explicitly calculate the induced gravity theory at the boundary of an asymptotically Anti-de Sitter five dimensional Einstein gravity. We also display the action that encodes the dynamics of radial diffeomorphisms. It is found that the…

High Energy Physics - Theory · Physics 2008-11-26 Rodrigo Aros , Mauricio Romo , Nelson Zamorano

The theory described by the sum of the Einstein-Hilbert action and the action of conformal scalar field possesses the duality symmetry which includes some special conformal transformation of the metric, and also inversion of scalar field…

High Energy Physics - Theory · Physics 2009-10-30 I. L. Shapiro

The conformal gravity is one of the most important models of quantum gravity with higher derivatives. We investigate the role of the Gauss-Bonnet term in this theory. The coincidence limit of the second coefficient of the Schwinger-DeWitt…

High Energy Physics - Theory · Physics 2009-11-10 G. de Berredo-Peixoto , I. L. Shapiro

It is found that the induced gravity with conformal couplings requires the conformal invariance in both classical and quantum levels for consistency. This is also true for the induced gravity with an extended conformal coupling interacting…

General Relativity and Quantum Cosmology · Physics 2015-06-25 C. J. Park , Yongsung Yoon

We discuss the stabilization of the conformal factor by higher derivative terms in a conformally reduced $R+R^2$ Euclidean gravity theory. The flat spacetime is unstable towards the condensation of modes with nonzero momentum, and they…

High Energy Physics - Theory · Physics 2013-04-17 Alfio Bonanno , Martin Reuter

Motivated by recent evidence indicating that Quantum Einstein Gravity (QEG) might be nonperturbatively renormalizable, the exact renormalization group equation of QEG is evaluated in a truncation of theory space which generalizes the…

High Energy Physics - Theory · Physics 2008-11-26 O. Lauscher , M. Reuter

The conformal invariance of unimodular gravity survives quantum corrections, even in the presence of conformal matter. Unimodular gravity can actually be understood as a certain truncation of the full Einstein-Hilbert theory, where in the…

High Energy Physics - Theory · Physics 2015-06-12 Enrique Álvarez , Mario Herrero-Valea

The Wilsonian renormalization group (RG) requires Euclidean signature. The conformal factor of the metric then has a wrong-sign kinetic term, which has a profound effect on its RG properties. Generically for the conformal sector, complete…

High Energy Physics - Theory · Physics 2018-08-10 Tim R. Morris

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

We argue that 4D gravity is drastically modified at distances larger than the horizon scale, due to the large infrared quantum fluctuations of the conformal part of the metric. The infrared dynamics of the conformal factor is generated by…

High Energy Physics - Theory · Physics 2007-05-23 I. Antoniadis

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 renormalizability, we show that strict cutoff…

High Energy Physics - Theory · Physics 2007-05-23 P. Forgacs , M. Niedermaier

The normalization of the quantum corrected action is resolving the equation divergent dependence of the cutoff towards the system apparent result in quantum gravity. Here we consider the normalization to Einstein R twice scalar action with…

High Energy Physics - Theory · Physics 2025-02-25 Daiki Yamaguchi

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 the effective average action and is…

High Energy Physics - Theory · Physics 2015-02-12 Daniel Becker , Martin Reuter

A gauge theory of quantum gravity is formulated, in which an internal, field dependent metric is introduced which non-linearly realizes the gauge fields on the non-compact group $SL(2,C)$, while linearly realizing them on $SU(2)$.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. W. Moffat