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We give in this paper a modified self-dual action that leads to the $SO(3)$-ADM formalism without having to face the difficult second class constraints present in other approaches (for example if one starts from the Hilbert-Palatini…

General Relativity and Quantum Cosmology · Physics 2017-03-24 J. Fernando Barbero

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

I show in this letter that it is possible to solve some of the constraints of the $SO(3)$-ADM formalism for general relativity by using an approach similar to the one introduced by Capovilla, Dell and Jacobson to solve the vector and scalar…

General Relativity and Quantum Cosmology · Physics 2017-03-24 J. Fernando Barbero

We show that the reality conditions to be imposed on Ashtekar variables to recover real gravity can be implemented as second class constraints a la Dirac. Thus, counting gravitational degrees of freedom follows accordingly. Some constraints…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Hugo A. Morales-Tecotl , Luis F. Urrutia , J. David Vergara

We examine the constraints and the reality conditions that have to be imposed in the canonical theory of 4--d gravity formulated in terms of Ashtekar variables. We find that the polynomial reality conditions are consistent with the…

High Energy Physics - Theory · Physics 2010-04-06 Giorgio Immirzi

Using Ashtekar variables, we analyze Lorentzian and Euclidean gravity in vacuum up to a constant conformal transformation. We prove that the reality conditions are invariant under a Wick rotation of the time, and show that the compatibility…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Guillermo A. Mena Marugan

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

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

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

As basic variables in general relativity (GR) are chosen antisymmetric connection and bivectors - bilinear in tetrad area tensors subject to appropriate (bilinear) constraints. In canonical formalism we get theory with polinomial…

General Relativity and Quantum Cosmology · Physics 2007-05-23 V. Khatsymovsky

I show in this letter that it is possible to construct a Hamiltonian description for Lorentzian General Relativity in terms of two real $SO(3)$ connections. The constraints are simple polynomials in the basic variables. The present…

General Relativity and Quantum Cosmology · Physics 2017-03-24 J. Fernando Barbero

Superspace parametrized by gauge potentials instead of metric three-geometries is discussed in the context of the Ashtekar variables. Among other things, an "internal clock" for the full theory can be identified. Gauge-fixing conditions…

General Relativity and Quantum Cosmology · Physics 2010-11-01 Chopin Soo , Lay Nam Chang

I suggest in this letter a new strategy to attack the problem of the reality conditions in the Ashtekar approach to classical and quantum general relativity. By writing a modified Hamiltonian constraint in the usual $SO(3)$ Yang-Mills phase…

General Relativity and Quantum Cosmology · Physics 2017-03-24 J. Fernando Barbero

One can simplify the triad formulations of canonical gravity by abandoning any relation to a fixed coordinate system. That means in case of the \ADM formalism that one can determine the momentum by direct derivation of the Lagrange-3-form…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Joachim Schirmer

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

As shown by Ashtekar in the mid 80's, general relativity can be extended to incorporate degenerate metrics. This extension is not unique, however, as one can change the form of the hamiltonian constraints and obtain an {\it alternative}…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Joseph D. Romano

The form of the initial value constraints in Ashtekar's hamiltonian formulation of general relativity is recalled, and the problem of solving them is compared with that in the traditional metric variables. It is shown how the general…

General Relativity and Quantum Cosmology · Physics 2007-05-23 R. Capovilla , J. Dell , T. Jacobson

The present work has a double aim. On the one hand we call attention on the relationship existing between the Ashtekar formalism and other gauge-theoretical approaches to gravity, in particular the Poincar\'e Gauge Theory. On the other hand…

General Relativity and Quantum Cosmology · Physics 2009-11-11 A. Tiemblo , R. Tresguerres

We discuss reality conditions and the relation between spacetime diffeomorphisms and gauge transformations in Ashtekar's complex formulation of general relativity. We produce a general theoretical framework for the stabilization algorithm…

General Relativity and Quantum Cosmology · Physics 2009-10-31 J. M. Pons , D. C. Salisbury , L. C. Shepley

We advocate an alternative description of canonical gravity in 3+1 dimensions, obtained by using as the basic variable a real variant of the usual Ashtekar connection variables on the spatial three-manifold. With this ansatz, no non-trivial…

General Relativity and Quantum Cosmology · Physics 2007-05-23 R. Loll
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