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The Ashtekar variables have been use to find a number of exact solutions in quantum gravity and quantum cosmology. We investigate the origin of these solutions in the context of a number of canonical transformations (both complex and real)…

General Relativity and Quantum Cosmology · Physics 2012-08-27 J. Fernando Barbero , Michael P. Ryan,

The cosmological scalar perturbations of standard matter are investigated in the context of extended teleparallel $f(T)$ gravity theories using the $1+3$ covariant formalism. After a review of the background, gravitational field equations…

General Relativity and Quantum Cosmology · Physics 2020-06-24 Shambel Sahlu , Joseph Ntahompagaze , Amare Abebe , Alvaro de la Cruz-Dombriz , David F. Mota

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

In this work we investigate the canonical quantization of 2+1 gravity with cosmological constant $\Lambda>0$ in the canonical framework of loop quantum gravity. The unconstrained phase space of gravity in 2+1 dimensions is coordinatized by…

General Relativity and Quantum Cosmology · Physics 2012-08-15 Karim Noui , Alejandro Perez , Daniele Pranzetti

3D Loop Quantum Gravity with a vanishing cosmological constant can be related to the quantization of the $\textrm{SU}(2)$ BF theory discretized on a lattice. At the classical level, this discrete model characterizes discrete flat geometries…

General Relativity and Quantum Cosmology · Physics 2014-12-03 Valentin Bonzom , Maité Dupuis , Florian Girelli

The philosophy of the Loop Quantum Gravity approach is to construct the canonical variables by using the duality of infinitesimal connections and holonomies along loops. Based on this fundamental property for example the holonomy-flux…

General Relativity and Quantum Cosmology · Physics 2011-08-24 Diana Kaminski

From the Holst action in terms of complex valued Ashtekar variables additional reality conditions mimicking the linear simplicity constraints of spin foam gravity are found. In quantum theory with the results of You and Rovelli we are able…

General Relativity and Quantum Cosmology · Physics 2012-01-25 Wolfgang Wieland

We compute the one-loop contributions of the chronological products for massless gravity in the second order of the perturbation theory. We prove that the loop contributions are coboundaries i.e. expressions which give zero when averaged on…

High Energy Physics - Theory · Physics 2019-05-15 Dan-Radu Grigore

It is argued that quantum gravity has an interpretation as a topological field theory provided a certain constraint from the path intergral measure is respected. The constraint forces us to couple gauge and matter fields to gravity for…

High Energy Physics - Theory · Physics 2009-10-30 Andrew Toon

Loop quantum gravity has provided us with a canonical framework especially devised for background independent and diffeomorphism invariant gauge field theories. In this quantization the fundamental excitations are called spin network…

General Relativity and Quantum Cosmology · Physics 2010-09-28 Valentin Bonzom

We derive and discus the equations of motion for spinless matter: relativistic spinless scalar fields, particles and fluids in the recently proposed by A. Saa model of gravity with covariantly constant volume with respect to the transposed…

General Relativity and Quantum Cosmology · Physics 2015-06-25 P. P. Fiziev

We study the Hamiltonian formulation of the generally covariant theory defined by the Lagrangian 4-form L=e_I e_J F^{IJ}(\omega) where e^I is a tetrad field and F^{IJ} is the curvature of a Lorentz connection \omega^{IJ}. This theory can be…

General Relativity and Quantum Cosmology · Physics 2015-03-13 Lihui Liu , Merced Montesinos , Alejandro Perez

In this paper we will make a survey of solutions to the Wheeler-Dewitt equation which have been found up to now in Ashtekar's formulation for canonical quantum gravity. Roughly speaking they are classified into two categories, namely,…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Kiyoshi Ezawa

We quantise the new connection formulation of D+1 dimensional General Relativity developed in our companion papers by Loop Quantum Gravity (LQG) methods. It turns out that all the tools prepared for LQG straightforwardly generalise to the…

General Relativity and Quantum Cosmology · Physics 2013-02-13 Norbert Bodendorfer , Thomas Thiemann , Andreas Thurn

The Einstein-Hilbert action in three dimensions and the transformation rules for the dreibein and spin connection can be naturally described in terms of gauge theory. In this spirit, we use covariant coordinates in noncommutative gauge…

We introduce a new framework for loop quantum gravity: mimicking the spinfoam quantization procedure we propose to study the symmetric sectors of the theory imposing the reduction weakly on the full kinematical Hilbert space of the…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Emanuele Alesci , Francesco Cianfrani

The Hamilton-Jacobi analysis of three dimensional gravity defined in terms of Ashtekar-like variables is performed. We report a detailed analysis where the complete set of Hamilton-Jacobi constraints, the characteristic equations and the…

General Relativity and Quantum Cosmology · Physics 2020-02-28 Alberto Escalante , M. Eduardo Hernández-García

We review in simple terms the covariant approaches to the canonical formulation of classical relativistic field theories (in particular gauge field theories and general relativity) and we discuss the relationships between these approaches…

High Energy Physics - Theory · Physics 2023-12-06 Francois Gieres

We review the geometrical properties of vacuum spacetimes in (2+1)-gravity with vanishing cosmological constant. We explain how these spacetimes are characterised as quotients of their universal cover by holonomies. We explain how this…

General Relativity and Quantum Cosmology · Physics 2023-06-13 C. Meusburger

Quantum gravity coupled to scalar massive matter fields is investigated within the framework of causal perturbation theory. One-loop calculations include matter loop graviton self-energy and matter self-energy and yield ultraviolet finite…

High Energy Physics - Theory · Physics 2009-10-31 Nicola Grillo