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In Loop Quantum Gravity, tremendous progress has been made using the Ashtekar-Barbero variables. These variables, defined in a gauge-fixing of the theory, correspond to a parametrization of the solutions of the so-called simplicity…

General Relativity and Quantum Cosmology · Physics 2018-05-09 Christoph Charles

We examine the advantages of the SO(3)-ADM (Ashtekar) formulation of general relativity, from the point of following the dynamics of the Lorentzian spacetime in direction of applying this into numerical relativity. We describe our strategy…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Hisa-aki Shinkai , Gen Yoneda

In order to discuss the well-posed initial value formulation of the teleparallel gravity and apply it to numerical relativity a symmetric hyperbolic system in the self-dual teleparallel gravity which is equivalent to the Ashtekar…

General Relativity and Quantum Cosmology · Physics 2009-11-10 G. Y. Chee , Yongxin Guo

We consider the quantization of gravity as an SL(2,C) gauge theory in terms of Ashtekar's selfdual variables and reality conditions for the spatial metric (RCI) and its evolution (RCII). We start from a holomorphic phase space formulation.…

General Relativity and Quantum Cosmology · Physics 2023-10-31 Hanno Sahlmann , Robert Seeger

There is a gap that has been left open since the formulation of general relativity in terms of Ashtekar's new variables namely the treatment of asymptotically flat field configurations that are general enough to be able to define the…

General Relativity and Quantum Cosmology · Physics 2010-04-06 T. Thiemann

The Hilbert-Palatini (HP) Lagrangian of general relativity being written in terms of selfdual and antiselfdual variables contains Ashtekar Lagrangian (which governs the dynamics of the selfdual sector of the theory on condition that the…

General Relativity and Quantum Cosmology · Physics 2009-10-28 V. M. Khatsymovsky

In this paper we generalise previous work on tensor perturbations in a de Sitter background in terms of Ashtekar variables to cover all complex values of the Immirzi parameter gamma (previous work was restricted to imaginary gamma).…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Laura Bethke , Joao Magueijo

There is a gap that has been left open since the formulation of general relativity in terms of Ashtekar's new variables namely the treatment of asymptotically flat field configurations that are general enough to be able to define the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 T. Thiemann

We solve the complex Einstein equations for Bianchi I and II models formulated in the Ashtekar variables. We then solve the reality conditions to obtain a parametrization of the space of Lorentzian solutions in terms of real canonically…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Gabriela Gonzalez , Ranjeet S Tate

The BRST transformations for gravity in Ashtekar variables are obtained by using the Maurer-Cartan horizontality conditions. The BRST cohomology in Ashtekar variables is calculated with the help of an operator $\delta$ introduced by S.P.…

High Energy Physics - Theory · Physics 2009-10-28 P. A. Blaga , O. Moritsch , M. Schweda , T. Sommer , L. Tataru , H. Zerrouki

We show that within the Ashtekar formulation of General Relativity a considerably simple and compact form of the Lorentzian Hamiltonian constraint occurs for a particular value of the Barbero--Immirzi parameter.

General Relativity and Quantum Cosmology · Physics 2009-12-18 H. Balasin , W. Wieland

We introduce a reduced model for a real sector of complexified Ashtekar gravity that does not correspond to a subset of Einstein's gravity but for which the programme of canonical quantization can be carried out completely, both, via the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 T. Thiemann

We examine tensor perturbations around a deSitter background within the framework of Ashtekar's variables and cousins parameterized by the Immirzi parameter $\gamma$. At the classical level we recover standard cosmological perturbation…

General Relativity and Quantum Cosmology · Physics 2011-03-23 Joao Magueijo , Dionigi M. T. Benincasa

For various theories, in particular gauge field theories, the algebraic form of the Hamiltonian simplifies considerably if one writes it in terms of certain complex variables. Also general relativity when written in the new canonical…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Thomas Thiemann

In this paper we revisit the canonical analysis of $BF$ gravity with the Immirzi parameter and a cosmological constant. By examining the constraint on the $B$ field, we realize that the analysis can be performed in a Lorentz-covariant…

General Relativity and Quantum Cosmology · Physics 2020-04-27 Merced Montesinos , Mariano Celada

We present a manifestly Lorentz-covariant description of the phase space of general relativity with the Immirzi parameter. This formulation emerges after solving the second-class constraints arising in the canonical analysis of the Holst…

General Relativity and Quantum Cosmology · Physics 2018-01-17 Merced Montesinos , Jorge Romero , Mariano Celada

A manifestly diffeomorphism invariant extension of Einstein gravity is constructed, which includes singular metrics, and whose ADM formulation is Ashtekar's gravity. The latter is shown to be locally equivalent to the covariant theory. It…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Hans-Juergen Matschull

The canonical analysis of the (anti-) self-dual action for gravity supplemented with the (anti-) self-dual Pontrjagin term is carried out. The effect of the topological term is to add a `magnetic' term to the original momentum variable…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Merced Montesinos

The Kodama State for Lorentzian gravity presupposes a particular value for the Immirzi-parameter, namely $\beta=-i$. However, the derivation of black hole entropy in Loop Quantum Gravity suggests that the Immirzi parameter is a fixed value…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Andrew Randono

The Ashtekar-Renteln Ansatz gives the self-dual solutions to the Einstein equation. A direct generalization of the Ashtekar-Renteln An\-satz to N=1 supergravity is given both in the canonical and in the covariant formulation and a…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Géza Fülöp