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Related papers: The Barbero-Immirzi Parameter: An Enigmatic Parame…

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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 1-parameter family of transformations identified by Barbero and Immirzi plays a significant role in non-perturbative approaches to quantum gravity, among them Loop Quantum Gravity and Spin Foams. It facilitates the loop quantization…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Bianca Dittrich , James P. Ryan

The Immirzi parameter of loop quantum gravity is a one parameter ambiguity of the theory whose precise interpretation is not universally agreed upon. It is an inherent characteristic of the quantum theory as it appears in the spectra of…

General Relativity and Quantum Cosmology · Physics 2017-06-07 Patrick J. Wong

The Barbero-Immirzi parameter is a one parameter quantization ambiguity underpinning the loop approach to quantum gravity that bears tantalizing similarities to the theta parameter of gauge theories such as Yang-Mills and QCD. Despite the…

High Energy Physics - Theory · Physics 2011-01-17 Simone Mercuri , Andrew Randono

The emergence of loop quantum gravity over the past two decades has stimulated a great resurgence of interest in unifying general relativity and quantum mechanics. Amongst a number of appealing features of this approach are the intuitive…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Charles H. -T. Wang

Quantum black holes within the loop quantum gravity (LQG) framework are considered. The number of microscopic states that are consistent with a black hole of a given horizon area $A_0$ are counted and the statistical entropy, as a function…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Alejandro Corichi , Jacobo Diaz-Polo , Enrique Fernandez-Borja

We introduce a covariant formulation of Barbero-Immirzi connections, which are used in Loop Quantum Gravity to describe gravity. We show that Barbero-Immirzi connections can be uniquely defined out of a given spin connection for any…

Differential Geometry · Mathematics 2021-06-30 Andrea Orizzonte , Lorenzo Fatibene

This paper investigates the implications from area quantization in Loop Quantum Gravity, particularly focusing on the application of the Landauer principle -- a fundamental thermodynamic concept establishing a connection between information…

General Relativity and Quantum Cosmology · Physics 2025-09-16 Everton M. C. Abreu , Jorge Ananias Neto , Ronaldo Thibes

We reexmine some proposals of black hole entropy in loop quantum gravity (LQG) and consider a new possible choice of the Immirzi parameter which has not been pointed out so far. We also discuss that a new idea is inevitable if we regard the…

High Energy Physics - Theory · Physics 2009-11-11 Takashi Tamaki , Hidefumi Nomura

We consider Regge calculus in the representation in terms of area tensors and self- and antiselfdual connections generalised to the case of Holst action that is standard Einstein action in the tetrad-connection variables plus topological…

High Energy Physics - Theory · Physics 2008-04-21 V. M. Khatsymovsky

We construct and study Loop Quantum Cosmology (LQC) when the Barbero-Immirzi parameter takes the complex value $\gamma=\pm i$. We refer to this new quantum cosmology as complex Loop Quantum Cosmology. We proceed in making an analytic…

General Relativity and Quantum Cosmology · Physics 2015-06-22 Jibril Ben Achour , Julien Grain , Karim Noui

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

The Barbero-Immirzi parameter $\gamma$ appears in the \emph{real} connection formulation of gravity in terms of the Ashtekar variables, and gives rise to a one-parameter quantization ambiguity in Loop Quantum Gravity. In this paper we…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Tomas Liko

We argue for black hole entropy in loop quantum gravity (LQG) by taking into account the interpretation that there is no other side of the horizon. This gives new values for the Barbero-Immirzi parameter which are fairly larger than those…

High Energy Physics - Theory · Physics 2008-11-26 Takashi Tamaki

We embed the Loop Quantum Gravity Barbero-Immirzi parameter and field within an action describing 4D, $\cal N$ = 1 supergravity and thus within a Low Energy Effective Action of Superstring/M-Theory. We use the fully gauge-covariant…

High Energy Physics - Theory · Physics 2009-09-29 S. James Gates , Sergei V. Ketov , Nicolas Yunes

Quantum Geometry (the modern Loop Quantum Gravity using graphs and spin-networks instead of the loops) provides microscopic degrees of freedom that account for the black-hole entropy. However, the procedure for state counting used in the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Marcin Domagala , Jerzy Lewandowski

In loop quantum gravity, the number $N_\Gamma(A,\gamma)$ of microstates of a black hole for a given discrete geometry $\Gamma$ depends on the so-called Barbero-Immirzi parameter $\gamma$. Using a suitable analytic continuation of $\gamma$…

General Relativity and Quantum Cosmology · Physics 2014-07-08 Ernesto Frodden , Marc Geiller , Karim Noui , Alejandro Perez

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

In this paper, we analyse a curvature- and torsion-square quantum gravity action with an additional Holst term minimally coupled to a massive Dirac field in four dimensions. The main purpose here is to try to estimate and compare the value…

High Energy Physics - Theory · Physics 2014-12-17 Nelson Panza , Hilário Rodrigues , Denis Cocuroci , José Abdala Helayël-Neto

The continuum and semiclassical limits of isotropic, spatially flat loop quantum cosmology are discussed, with an emphasis on the role played by the Barbero-Immirzi parameter \gamma in controlling space-time discreteness. In this way,…

General Relativity and Quantum Cosmology · Physics 2010-05-28 Martin Bojowald
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