scholarly journals EFFECTIVE THEORY FOR QUANTUM GRAVITY

2013 ◽  
Vol 22 (12) ◽  
pp. 1342014 ◽  
Author(s):  
XAVIER CALMET
Keyword(s):  
Higgs Boson ◽  
Quantum Gravity ◽  
Effective Action ◽  
Binary Systems ◽  
Ricci Scalar ◽  
Effective Theory ◽  
Nonminimal Coupling ◽  
Order Unity

In this paper, we discuss an effective theory for quantum gravity and discuss the bounds on the parameters of this effective action. In particular, we show that measurement in pulsars binary systems are unlikely to improve the bounds on the coefficients of the R2 and RμνRμν terms obtained from probes of Newton's potential performed on Earth. Furthermore, we argue that if the coefficients of these terms are induced by quantum gravity, they should be at most of order unity since R2 and RμνRμν are dimension four operators. The same applies to the nonminimal coupling of the Higgs boson to the Ricci scalar.

scholarly journals Derive Lovelock gravity from string theory in cosmological background

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Peng Wang ◽  
Houwen Wu ◽  
Haitang Yang ◽  
Shuxuan Ying
Keyword(s):  
String Theory ◽  
Effective Action ◽  
Strong Support ◽  
Effective Theory ◽  
Quadratic Term ◽  
Lovelock Gravity ◽  
Cosmological Background ◽  
Finite Term ◽  
Specific Dimension ◽  
Bonnet Term

Abstract It was proved more than three decades ago, that the first order α′ correction of string effective theory could be written as the Gauss-Bonnet term, which is the quadratic term of Lovelock gravity. In cosmological background, with an appropriate field redefinition, we reorganize the infinite α′ corrections of string effective action into a finite term expression for any specific dimension. This finite term expression matches Lovelock gravity exactly and thus fix the couplings of Lovelock gravity by the coefficients of string effective action. This result thus provides a strong support to string theory.

scholarly journals Holographic Formulation of 3D Metric Gravity with Finite Boundaries

Universe ◽  
2019 ◽  
Vol 5 (8) ◽  
pp. 181 ◽  
Author(s):  
Seth Asante ◽  
Bianca Dittrich ◽  
Florian Hopfmueller
Keyword(s):  
Effective Action ◽  
Boundary Point ◽  
Ricci Scalar ◽  
General Family ◽  
Geodesic Length ◽  
Geometric Boundary ◽  
3D Gravity

In this work we construct holographic boundary theories for linearized 3D gravity, for a general family of finite or quasi-local boundaries. These boundary theories are directly derived from the dynamics of 3D gravity by computing the effective action for a geometric boundary observable, which measures the geodesic length from a given boundary point to some center in the bulk manifold. We identify the general form for these boundary theories and find that these are Liouville-like with a coupling to the boundary Ricci scalar. This is illustrated with various examples, which each offer interesting insights into the structure of holographic boundary theories.

PERTURBATIVE FINITENESS OF 2D INDUCED QUANTUM GRAVITY

1992 ◽  
Vol 07 (05) ◽  
pp. 437-440 ◽  
Author(s):  
S.D. ODINTSOV ◽  
I.L. SHAPIRO
Keyword(s):  
Quantum Gravity ◽  
Effective Action ◽  
General Type ◽  
Full Agreement ◽  
Exactly Solvable ◽  
Covariant Gauge ◽  
Generally Covariant

The divergences structure of the local 2D induced quantum gravity in the generally covariant gauge of the general type is considered. It is shown that for the particular choice of this gauge the effective action is perturbatively finite. This fact is in full agreement with the fact that the theory is exactly solvable.

scholarly journals WILSONIAN BLACK HOLE ENTROPY IN QUANTUM GRAVITY

1996 ◽  
Vol 11 (16) ◽  
pp. 2823-2834
Author(s):  
SERGEI D. ODINTSOV ◽  
YONGSUNG YOON
Keyword(s):  
Black Hole ◽  
Renormalization Group ◽  
Quantum Gravity ◽  
Black Hole Entropy ◽  
Conformal Factor ◽  
Infrared Region ◽  
Coupling Constants ◽  
Effective Theory ◽  
Free Form ◽  
Renormalization Group Equations

Using the Wilsonian procedure (renormalization group improvement) we discuss the finite quantum corrections to black hole entropy in renormalizable theories. In this way, the Wilsonian black hole entropy is found for GUT’s (of asymptotically free form, in particular) and for the effective theory for the conformal factor aiming to describe quantum gravity in the infrared region. The off-critical regime (where the coupling constants are running) for the effective theory for the conformal factor in quantum gravity (with or without torsion) is explicitly constructed. The corresponding renormalization group equations for the effective couplings are found using the Schwinger-DeWitt technique for the calculation of the divergences of the fourth order operator.

scholarly journals 2D QUANTUM GRAVITY COUPLED TO RENORMALIZABLE MATTER FIELDS

1994 ◽  
Vol 09 (32) ◽  
pp. 5689-5709 ◽  
Author(s):  
JAN AMBJØRN ◽  
KAZUO GHOROKU
Keyword(s):  
Renormalization Group ◽  
Quantum Gravity ◽  
Effective Action ◽  
Two Dimensional ◽  
Conformally Invariant ◽  
Renormalization Group Equations ◽  
Β Function ◽  
Matter Fields

We consider two-dimensional quantum gravity coupled to matter fields which are renormalizable but not conformally invariant. Questions concerning the β function and the effective action are addressed, and the effective action and the dressed renormalization group equations are determined for various matter potentials.

TWO-LOOP APPROACH TO THE EFFECTIVE ACTION IN QUANTUM GRAVITY

1992 ◽  
Vol 07 (14) ◽  
pp. 3203-3233 ◽  
Author(s):  
I. L. BUCHBINDER ◽  
S. D. ODINTSOV ◽  
O. A. FONAREV
Keyword(s):  
Quantum Gravity ◽  
Cosmological Constant ◽  
Minkowski Space ◽  
Effective Action ◽  
Dimensional Regularization ◽  
Dimensional Torus ◽  
Spontaneous Compactification ◽  
Metric Tensor ◽  
First Time

For the first time we present the general formalism and results of calculation of the two-loop effective action in Einstein quantum gravity on the background MN × Tk, where MN is Minkowski space and Tk is a k-dimensional torus. We discuss the case of a zero cosmological constant as well as of a nonzero one. The method of calculating variations of the action on a metric tensor and the technique of calculating momentum integrals in dimensional regularization are presented. Some applications to spontaneous compactification are discussed, as well as some prospects.

scholarly journals NONCOMMUTATIVE BLACK HOLES, THE FINAL APPEAL TO QUANTUM GRAVITY: A REVIEW

2009 ◽  
Vol 24 (07) ◽  
pp. 1229-1308 ◽  
Author(s):  
PIERO NICOLINI
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Quantum Gravity ◽  
Effective Theory ◽  
Final State ◽  
Curved Space ◽  
Higher Dimensional ◽  
Energy Hadron ◽  
Black Hole Remnant ◽  
First Time

We present the state of the art regarding the relation between the physics of Quantum Black Holes and Noncommutative Geometry. We start with a review of models proposed in the literature for describing deformations of General Relativity in the presence of noncommutativity, seen as an effective theory of Quantum Gravity. We study the resulting metrics, proposed to replace or at least to improve the conventional black hole solutions of Einstein's equation. In particular, we analyze noncommutative-inspired solutions obtained in terms of quasiclassical noncommutative coordinates: indeed because of their surprising new features, these solutions enable us to circumvent long standing problems with Quantum Field Theory in Curved Space and to cure the singular behavior of gravity at the centers of black holes. As a consequence, for the first time, we get a complete description of what we may call the black hole SCRAM, the shut down of the emission of thermal radiation from the black hole: in place of the conventional scenario of runaway evaporation in the Planck phase, we find a zero temperature final state, a stable black hole remnant, whose size and mass are determined uniquely in terms of the noncommutative parameter θ. This result turns out to be of vital importance for the physics of the forthcoming experiments at the LHC, where mini black hole production is foreseen in extreme energy hadron collisions. Because of this, we devote the final part of this review to higher-dimensional solutions and their phenomenological implications for TeV Gravity.

scholarly journals SPONTANEOUS COMPACTIFICATION IN 2D INDUCED QUANTUM GRAVITY

1992 ◽  
Vol 07 (26) ◽  
pp. 2369-2376 ◽  
Author(s):  
E. ELIZALDE ◽  
S. D. ODINTSOV
Keyword(s):  
Quantum Gravity ◽  
Effective Action ◽  
Spontaneous Compactification

Spontaneous compactification – on a R1 × S1 background – in 2D induced quantum gravity (considered as a toy model for more fundamental quantum gravity) is analyzed in the gauge-independent effective action formalism. It is shown that such compactification is stable, in contradistinction to multidimensional quantum gravity on a RD × S1(D > 2) background – which is known to be one-loop unstable.

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