scholarly journals ON THE POSSIBILITY OF QUANTUM GRAVITY EFFECTS AT ASTROPHYSICAL SCALES

2006 ◽  
Vol 15 (12) ◽  
pp. 2011-2028 ◽  
Author(s):  
MARTIN REUTER ◽  
HOLGER WEYER
Keyword(s):  
Dark Matter ◽  
Renormalization Group ◽  
Quantum Gravity ◽  
Einstein Gravity ◽  
Scale Dependence ◽  
Renormalization Group Flow ◽  
Gravity Effects ◽  
Group Flow ◽  
Nonperturbative Renormalization

The nonperturbative renormalization group flow of quantum Einstein gravity (QEG) is reviewed. It is argued that at large distances there could be strong renormalization effects, including a scale dependence of Newton's constant, which mimic the presence of dark matter at galactic and cosmological scales.

scholarly journals ASYMPTOTIC SAFETY IN HIGHER-DERIVATIVE GRAVITY

2009 ◽  
Vol 24 (28) ◽  
pp. 2233-2241 ◽  
Author(s):  
DARIO BENEDETTI ◽  
PEDRO F. MACHADO ◽  
FRANK SAUERESSIG
Keyword(s):  
Fixed Point ◽  
Renormalization Group ◽  
Renormalization Group Flow ◽  
Functional Renormalization Group ◽  
Asymptotic Safety ◽  
Higher Derivative ◽  
Gravity Theories ◽  
Group Flow ◽  
Nonperturbative Renormalization

We study the nonperturbative renormalization group flow of higher-derivative gravity employing functional renormalization group techniques. The nonperturbative contributions to the β-functions shift the known perturbative ultraviolet fixed point into a nontrivial fixed point with three UV-attractive and one UV-repulsive eigendirections, consistent with the asymptotic safety conjecture of gravity. The implication of this transition on the unitarity problem, typically haunting higher-derivative gravity theories, is discussed.

scholarly journals IRREVERSIBILITY OF THE RENORMALIZATION GROUP FLOW IN TWO-DIMENSIONAL QUANTUM GRAVITY

1992 ◽  
Vol 07 (31) ◽  
pp. 2943-2955 ◽  
Author(s):  
DAVID KUTASOV
Keyword(s):  
Renormalization Group ◽  
String Theory ◽  
Quantum Gravity ◽  
Degrees Of Freedom ◽  
Two Dimensional ◽  
Renormalization Group Flow ◽  
Group Flow

We argue that the torus partition sum in 2D (super) gravity, which counts physical states in the theory, is a decreasing function of the renormalization group scale. As an application we chart the space of [Formula: see text] models coupled to (super) gravity, confirming and extending ideas due to A. Zamolodchikov, and discuss briefly string theory, where our results imply that the number of degrees of freedom decreases with time.

scholarly journals On the Vilkovisky-DeWitt approach and renormalization group in effective quantum gravity

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Breno L. Giacchini ◽  
Tibério de Paula Netto ◽  
Ilya L. Shapiro
Keyword(s):  
Renormalization Group ◽  
Quantum Gravity ◽  
Effective Action ◽  
Planck Scale ◽  
Renormalization Group Flow ◽  
Higher Derivative ◽  
Gauge Fixing ◽  
Total Action ◽  
The One ◽  
Group Flow

Abstract The effective action in quantum general relativity is strongly dependent on the gauge-fixing and parametrization of the quantum metric. As a consequence, in the effective approach to quantum gravity, there is no possibility to introduce the renormalization-group framework in a consistent way. On the other hand, the version of effective action proposed by Vilkovisky and DeWitt does not depend on the gauge-fixing and parametrization off- shell, opening the way to explore the running of the cosmological and Newton constants as well as the coefficients of the higher-derivative terms of the total action. We argue that in the effective framework the one-loop beta functions for the zero-, two- and four-derivative terms can be regarded as exact, that means, free from corrections coming from the higher loops. In this perspective, the running describes the renormalization group flow between the present-day Hubble scale in the IR and the Planck scale in the UV.

scholarly journals Unimodular quantum gravity: steps beyond perturbation theory

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Gustavo P. de Brito ◽  
Antonio D. Pereira
Keyword(s):  
Fixed Point ◽  
Perturbation Theory ◽  
Renormalization Group ◽  
Quantum Gravity ◽  
Symmetry Breaking ◽  
Coarse Graining ◽  
Renormalization Group Flow ◽  
Anomalous Dimensions ◽  
Group Flow

Abstract The renormalization group flow of unimodular quantum gravity is computed by taking into account the graviton and Faddeev-Popov ghosts anomalous dimensions. In this setting, a ultraviolet attractive fixed point is found. Symmetry-breaking terms induced by the coarse-graining procedure are introduced and their impact on the flow is analyzed. A discussion on the equivalence of unimodular quantum gravity and standard full diffeomorphism invariant theories is provided beyond perturbation theory.

scholarly journals SCALAR-QED β-FUNCTIONS NEAR PLANCK'S SCALE

1998 ◽  
Vol 13 (31) ◽  
pp. 5425-5441 ◽  
Author(s):  
GENTIL O. PIRES
Keyword(s):  
Renormalization Group ◽  
Effective Action ◽  
Coupling Parameter ◽  
Analytic Solutions ◽  
Einstein Gravity ◽  
Scalar Coupling ◽  
Threshold Effects ◽  
Renormalization Group Flow ◽  
Flow Equations ◽  
Group Flow

The Renormalization Group Flow Equations of the Scalar-QED model near Planck's scale are computed within the framework of the average effective action. Exact Flow Equations, corrected by Einstein Gravity, for the running self-interacting scalar coupling parameter and for the running v.e.v. of ϕ*ϕ, are computed taking into account threshold effects. Analytic solutions are given in the infrared and ultraviolet limits.

scholarly journals Ruppeiner curvature along a renormalization group flow

2021 ◽  
pp. 136450
Author(s):  
Pavan Kumar Yerra ◽  
Chandrasekhar Bhamidipati
Keyword(s):  
Renormalization Group ◽  
Renormalization Group Flow ◽  
Group Flow
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