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Related papers: The Immirzi Parameter as an Instanton Angle

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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 ($\gamma$) 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

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

Using quadratic spinor techniques we demonstrate that the Immirzi parameter can be expressed as ratio between scalar and pseudo-scalar contributions in the theory and can be interpreted as a measure of how Einstein gravity differs from a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Chung-Hsien Chou , Roh-Suan Tung , Hoi-Lai Yu

Barbero has generalized the Ashtekar canonical transformation to a one-parameter scale transformation $U(\iota)$ on the phase space of general relativity. Immirzi has noticed that in loop quantum gravity this transformation alters the…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Carlo Rovelli , Thomas Thiemann

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

A general argument provides the motivation to consider the Barbero--Immirzi parameter as a field. The specific form of the geometrical effective action allows to relate the value of the Barbero--Immirzi parameter to other quantum…

General Relativity and Quantum Cosmology · Physics 2009-09-02 Simone Mercuri

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

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 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

A possible topological interpretation of the Barbero-Immirzi parameter is proposed. Classically, by generalizing the Holst action to torsional spacetimes, we construct a precise analogy between the Barbero--Immirzi parameter and the…

General Relativity and Quantum Cosmology · Physics 2009-04-12 Simone Mercuri

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 Ashtekar-Barbero formulation of general relativity admits a one-parameter family of canonical transformations that preserves the expressions of the Gauss and diffeomorphism constraints. The loop quantization of the connection formalism…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Guillermo A. Mena Marugan

We consider gravity in 2+1 space-time dimensions, with negative cosmological constant and a `Barbero-Immirzi' (B-I) like parameter, when the space-time topology is of the form $ T^2 \times \mathbbm{R}$. The phase space structure, both in…

General Relativity and Quantum Cosmology · Physics 2010-05-07 Rudranil Basu , Samir K Paul

We set up a canonical Hamiltonian formulation for a theory of gravity based on a Lagrangian density made up of the Hilbert-Palatini term and, instead of the Holst term, the Nieh-Yan topological density. The resulting set of constraints in…

General Relativity and Quantum Cosmology · Physics 2009-09-02 Ghanashyam Date , Romesh K. Kaul , Sandipan Sengupta

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

The Immirzi ambiguity arises in loop quantum gravity when geometric operators are represented in terms of different connections that are related by means of an extended Wick transform. We analyze the action of this transform in gravity…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Luis J. Garay , Guillermo A. Mena Marugan

The Barbero-Immirzi parameter $\gamma$ appears as a coupling constant in the spinfoam dynamics of loop quantum gravity. In this work, we highlight that $\gamma$ can be understood as a measure of gravitational parity violation via a duality…

General Relativity and Quantum Cosmology · Physics 2026-04-28 Eugenio Bianchi , Monica Rincon-Ramirez

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 study perturbative quantum gravity in the first-order tetrad formalism. The lowest order action corresponds to Einstein-Cartan plus a parity-odd term, and is known in the literature as the Holst action. The coupling constant of the…

High Energy Physics - Theory · Physics 2011-07-04 Dario Benedetti , Simone Speziale
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