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Using self dual Ashtekar variables, we investigate (at the effective level) the spherically symmetry reduced model of loop quantum gravity, both in vacuum and when coupled to a scalar field. Within the real Ashtekar-Barbero formulation, the…

General Relativity and Quantum Cosmology · Physics 2017-07-12 Jibril Ben Achour , Suddhasattwa Brahma , Antonino Marciano

Spherically symmetric models of loop quantum gravity have been studied recently by different methods that aim to deal with structure functions in the usual constraint algebra of gravitational systems. As noticed by Gambini and Pullin, a…

General Relativity and Quantum Cosmology · Physics 2015-09-09 Martin Bojowald , Suddhasattwa Brahma , Juan D. Reyes

We study the dynamics of the scalar modes of linear perturbations around a flat, homogeneous and isotropic background in loop quantum cosmology. The equations of motion include quantum geometry effects and hold at all curvature scales so…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Edward Wilson-Ewing

Loop quantum gravity corrections, in the presence of inhomogeneities, can lead to a deformed constraint algebra. Such a deformation implies that the effective theory is no longer generally covariant. As a consequence, the geometrical…

General Relativity and Quantum Cosmology · Physics 2015-06-17 Rakesh Tibrewala

In this work a loop quantum corrected model is obtained for spherically symmetric space-times in the vacuum. This effective model is derived by the use of the path integral method, previously employed in several models of Loop Quantum…

General Relativity and Quantum Cosmology · Physics 2026-05-21 Juan Carlos Del Águila , Hugo A. Morales

In this paper we construct the Hamiltonian constraint operator of loop quantum cosmology using holonomies defined for arbitrary irreducible SU(2) representations labeled by spin J. We show that modifications to the effective semi-classical…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Kevin Vandersloot

We study spherical charged black holes in the presence of a cosmological constant with corrections motivated by the theory of loop quantum gravity. The effective theory is constructed at the Hamiltonian level by introducing certain…

General Relativity and Quantum Cosmology · Physics 2023-04-12 Asier Alonso-Bardaji , David Brizuela , Raül Vera

The cosmological primordial power spectrum is known to be one of the most promising observable to probe quantum gravity effects. In this article, we investigate how the tensor power spectrum is modified by Loop Quantum Gravity corrections.…

General Relativity and Quantum Cosmology · Physics 2010-04-06 J. Grain , T. Cailleteau , A. Barrau , A. Gorecki

The propagation of perturbations is studied with generalized holonomy corrections in a fully consistent way, ensuring that the deformed algebra of constraints remains closed. The primordial cosmological power spectra are calculated. It is…

General Relativity and Quantum Cosmology · Physics 2023-06-28 Maxime De Sousa , Killian Martineau , Cyril Renevey , Aurélien Barrau

Using the complex-valued self-dual connection variables, the loop quantum cosmology of a closed Friedmann universe coupled to a massless scalar field is studied. It is shown how the reality conditions can be imposed in the quantum theory by…

General Relativity and Quantum Cosmology · Physics 2016-04-07 Edward Wilson-Ewing

A systematic approach is developed in order to obtain spherically symmetric midisuperspace models that accept holonomy modifications in the presence of matter fields with local degrees of freedom. In particular, starting from the most…

General Relativity and Quantum Cosmology · Physics 2022-08-12 Asier Alonso-Bardaji , David Brizuela

We investigate the scalar mode of perturbation of super inflation in the version of loop quantum cosmology in which the gauge invariant holonomy corrections are considered. Given a background solution, we calculate the power spectrum of the…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Xiao-Jun Yue , Jian-Yang Zhu

In the framework of loop quantum cosmology anomaly free quantizations of the Hamiltonian constraint for Bianchi class A, locally rotationally symmetric and isotropic models are given. Basic ideas of the construction in (non-symmetric) loop…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Martin Bojowald

Since there are quantization ambiguities in constructing the Hamiltonian constraint operator in isotropic loop quantum cosmology, it is crucial to check whether the key features of loop quantum cosmology are robust against the ambiguities.…

General Relativity and Quantum Cosmology · Physics 2010-04-14 Jinsong Yang , You Ding , Yongge Ma

Loop quantum cosmology is a symmetry reduced quantization of cosmological spacetimes based on loop quantum gravity. While it has been successful in resolution of various cosmological singularities and connecting Planck scale physics to…

General Relativity and Quantum Cosmology · Physics 2019-12-25 Klaus Liegener , Parampreet Singh

The improved lattice regularization method of the Ashtekar connection holonomy representation in loop quantum gravity is described in this article. The approach is based on the geometric expansion of holonomies into power series up to the…

General Relativity and Quantum Cosmology · Physics 2021-05-31 Jakub Bilski

Since there are quantization ambiguities in constructing the Hamiltonian constraint operator in isotropic loop quantum cosmology, it is crucial to check whether the key features of loop quantum cosmology, such as the quantum bounce and…

General Relativity and Quantum Cosmology · Physics 2009-04-28 Jinsong Yang , You Ding , Yongge Ma

Cosmological perturbation equations are derived systematically in a canonical scheme based on Ashtekar variables. A comparison with the covariant derivation and various subtleties in the calculation and choice of gauges are pointed out.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Hector H. Hernández , Mikhail Kagan , Parampreet Singh , Aureliano Skirzewski

The detailed formulation of loop quantum cosmology with higher order holonomy corrections has been constructed recently in the homogeneous and isotropic spacetime, yet it is important to extend the higher order holonomy corrections to…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Xiao-Jun Yue , Jian-Yang Zhu

The scheme of using the Chern-Simons action to regularize the gravitational Hamiltonian constraint is extended to including the Lorentzian term in the $k=0$ cosmological model. The Euclidean term and the Lorenzian term are thus regularized…

General Relativity and Quantum Cosmology · Physics 2020-10-12 Jinsong Yang , Cong Zhang , Yongge Ma