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Related papers: Immirzi parameter without Immirzi ambiguity: Confo…

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We study the role of the Barbero-Immirzi parameter $\gamma$ and the choice of connection in the construction of (a symmetry-reduced version of) loop quantum gravity. We start with the four-dimensional Lorentzian Holst action that we reduce…

General Relativity and Quantum Cosmology · Physics 2015-05-19 Jibril Ben Achour , Marc Geiller , Karim Noui , Chao Yu

The Barbero-Immirzi parameter ($\gamma$) is introduced in loop quantum gravity (LQG) whose physical significance is still a biggest open question; because of its profound traits. In some cases, it is real-valued; while, it is complex-valued…

General Relativity and Quantum Cosmology · Physics 2022-09-22 Rakshit P. Vyas , Mihir J. Joshi

An so(4,C)-covariant hamiltonian formulation of a family of generalized Hilbert-Palatini actions depending on a parameter (the so called Immirzi parameter) is developed. It encompasses the Ashtekar-Barbero gravity which serves as a basis of…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Sergei Alexandrov

We present the Hamiltonian formulation of General Relativity with the Holst formulation in a generic local Lorentz frame. In particular, we outline that a Gauss constraint is inferred by a proper generalization of Ashtekar-Barbero-Immirzi…

General Relativity and Quantum Cosmology · Physics 2009-04-06 Francesco Cianfrani , Giovanni Montani

In Loop Quantum Gravity the classical point of departure is the Einstein-Hilbert action modified by the addition of the so-called Holst term. Classically, this term does not affect the equations of motion, but it induces a well-known…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Simone Mercuri , Victor Taveras

We calculate the one-loop divergences for quantum gravity with cosmological constant, using new parametrization of quantum metric. The conformal factor of the metric is treated as an independent variable. As a result the theory possesses an…

General Relativity and Quantum Cosmology · Physics 2011-04-12 G. de Berredo-Peixoto , A. B. Penna-Firme , I. L. Shapiro

We study the problem of how to derive conformal symmetry in the framework of quantum gravity. We start with a generic gravitational theory which is invariant under both the general coordinate transformation (GCT) and Weyl transformation (or…

High Energy Physics - Theory · Physics 2024-03-08 Ichiro Oda

To study asymptotic structures, we regularize Einstein's field equations by means of conformal transformations. The conformal factor is chosen so that it carries a dimensional scale that captures crucial asymptotic features. By choosing a…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Niklas Rohr , Claes Uggla

We consider some aspects of conformal symmetry in a metric-scalar-torsion system. It is shown that, for some special choice of the action, torsion acts as a compensating field and the full theory is conformally equivalent to General…

General Relativity and Quantum Cosmology · Physics 2009-10-31 J. A. Helayel-Neto , A. Penna-Firme , I. L. Shapiro

Fundamental quantum gravity theories are known to be notoriously difficult to extract viable testable predictions out of. In this paper, we aim to incorporate putative quantum corrections coming from loop quantum gravity in deriving…

General Relativity and Quantum Cosmology · Physics 2017-02-15 Suddhasattwa Brahma , Michele Ronco , Giovanni Amelino-Camelia , Antonino Marciano

In the context of Loop Quantum Gravity (LQG), we study the fate of Thiemann complexifier in homogeneous and isotropic FRW cosmology. The complexifier is the dilatation operator acting on the canonical phase space for gravity and generates…

General Relativity and Quantum Cosmology · Physics 2017-09-27 Jibril Ben Achour , Etera R. Livine

Several recent results have hinted that black hole thermodynamics in loop quantum gravity simplifies if one chooses an imaginary Barbero-Immirzi parameter $\gamma=i$. This suggests a connection with $\mathrm{SL}(2,\mathbb{C})$ or…

General Relativity and Quantum Cosmology · Physics 2015-08-06 S. Carlip

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

In this paper, by making use of the perturbative expansion around topological field theory we are trying to understand why the standard perturbation theory for General Relativity, which starts with linearized gravity does not see…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. Kowalski-Glikman , A. Starodubtsev

We consider a loop-quantum gravity inspired modification of general relativity, where the Holst action is generalized by making the Barbero-Immirzi (BI) parameter a scalar field, whose value could be dynamically determined. The modified…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Victor Taveras , Nicolas Yunes

The Immirzi parameter is a constant appearing in the general relativity action used as a starting point for the loop quantization of gravity. The parameter is commonly believed not to show up in the equations of motion, because it appears…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Alejandro Perez , Carlo Rovelli

With the present trend in experimental particle physics of probing yet shorter distances and with the requirement on the theoretical side of renormalizability, conformal invariance becomes an attractive symmetry for particle interactions.…

High Energy Physics - Theory · Physics 2022-08-29 A. D. Alhaidari

The configuration space of the reduced Hamiltonian formulation of quantum gravity has been shown, for non-Ricci flat metrics, to be a higher-dimensional analogue of the Teichm\"{u}ller space of conformal structures on a Riemann surface. In…

General Relativity and Quantum Cosmology · Physics 2012-08-21 James A. Reid , Charles H. -T. Wang

Microscopic state counting for a black hole in Loop Quantum Gravity yields a result proportional to horizon area, and inversely proportional to Newton's constant and the Immirzi parameter. It is argued here that before this result can be…

General Relativity and Quantum Cosmology · Physics 2010-10-27 Ted Jacobson

We consider the background-independent quantization of a general scale-invariant theory of gravity with matter, which supports a conserved Weyl current recently suggested as a natural flow of time. For scalar-metric systems, a conformal…

General Relativity and Quantum Cosmology · Physics 2019-11-21 Charles H. -T. Wang , Marcin Stankiewicz