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We propose a quantum symmetry reduction of loop quantum gravity to Bianchi I spacetimes. To this end, we choose the diagonal metric gauge for the spatial diffeomorphism constraint at the classical level, leading to an…

General Relativity and Quantum Cosmology · Physics 2015-04-16 Norbert Bodendorfer

The linearly polarized Gowdy $T^3$ model can be regarded as compact Bianchi I cosmologies with inhomogeneous modes allowed to travel in one direction. We study a hybrid quantization of this model that combines the loop quantization of the…

General Relativity and Quantum Cosmology · Physics 2015-05-20 M Martín-Benito , L J Garay , G A Mena Marugán

We present results concerning the nature of the cosmological big bounce(BB) transition within the loop geometry underlying loop quantum cosmology (LQC). Our canonical quantization method is an alternative to the standard LQC. An evolution…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Wlodzimierz Piechocki

We analyze the big bounce transition of the quantum FRW model in the setting of the nonstandard loop quantum cosmology (LQC). Elementary observables are used to quantize composite observables. The spectrum of the energy density operator is…

General Relativity and Quantum Cosmology · Physics 2011-03-28 Przemyslaw Malkiewicz , Wlodzimierz Piechocki

In this work, the quantization of the most general Bianchi Type I geometry, with and without a cosmological constant, is considered. In the spirit of identifying and subsequently removing as many gauge degrees of freedom as possible, a…

General Relativity and Quantum Cosmology · Physics 2008-11-26 T. Christodoulakis , T. Gakis , G. O. Papadopoulos

The "improved dynamics" of loop quantum cosmology is extended to include anisotropies of the Bianchi I model. As in the isotropic case, a massless scalar field serves as a relational time parameter. However, the extension is non-trivial…

General Relativity and Quantum Cosmology · Physics 2010-04-14 Abhay Ashtekar , Edward Wilson-Ewing

A loop quantization of the diagonal class A Bianchi models starting from the complex-valued self-dual connection variables is presented in this paper. The basic operators in the quantum theory correspond to areas and generalized holonomies…

General Relativity and Quantum Cosmology · Physics 2016-04-13 Edward Wilson-Ewing

Loop quantization of diagonalized Bianchi class A models, leads to a partial difference equation as the Hamiltonian constraint at the quantum level. A criterion for testing a viable semiclassical limit has been formulated in terms of…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Ghanashyam Date

Isotropic models in loop quantum cosmology allow explicit calculations, thanks largely to a completely known volume spectrum, which is exploited in order to write down the evolution equation in a discrete internal time. Because of genuinely…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Martin Bojowald

Volume operators measuring the total volume of space in a loop quantum theory of cosmological models are constructed. In the case of models with rotational symmetry an investigation of the Higgs constraint imposed on the reduced connection…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Martin Bojowald

We consider a simple cosmological model consisting of an empty Bianchi I Universe, whose Hamiltonian we deparametrise to provide a natural clock variable. The model thus effectively describes an isotropic universe with an induced clock…

General Relativity and Quantum Cosmology · Physics 2022-01-26 Przemysław Małkiewicz , Patrick Peter , S. D. P. Vitenti

The loop quantum cosmology "improved dynamics" of the Bianchi type IX model are studied. The action of the Hamiltonian constraint operator is obtained via techniques developed for the Bianchi type I and type II models, no new input is…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Edward Wilson-Ewing

Due to the numerical complexities of studying evolution in an anisotropic quantum spacetime, in comparison to the isotropic models, the physics of loop quantized anisotropic models has remained largely unexplored. In particular, robustness…

General Relativity and Quantum Cosmology · Physics 2017-04-14 Peter Diener , Anton Joe , Miguel Megevand , Parampreet Singh

A Bianchi type-I cosmological model in the presence of a magnetic flux along a cosmological string is considered. The first objective of this study is to investigate Einstein equations using a tractable assumption usually accepted in the…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Victor Rikhvitsky , Bijan Saha , Mihai Visinescu

In this work, we are investigating the problem of integrability of Bianchi class A cosmological models. This class of systems is reduced to the form of Hamiltonian systems with exponential potential forms. The dynamics of Bianchi class A…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Andrzej J. Maciejewski , Marek Szydlowski

We provide a quantum picture for the emergence of a bouncing cosmology, according to the idea that a semiclassical behavior of the Universe towards the singularity is not available in many relevant Minisuperspace models. In particular, we…

General Relativity and Quantum Cosmology · Physics 2022-09-07 Eleonora Giovannetti , Giovanni Montani

A simplified theory of the diagonal Bianchi type I model coupled with a massless scalar field in loop quantum cosmology is constructed according to the $\bar{\mu}$ scheme. Kinematical and physical sectors of the theory are under good…

General Relativity and Quantum Cosmology · Physics 2009-02-20 Lukasz Szulc

We derive a Hamiltonian formulation of the theory of gauge invariant, linear perturbations in anisotropic Bianchi I spacetimes, and describe how to quantize this system. The matter content is assumed to be a minimally coupled scalar field…

General Relativity and Quantum Cosmology · Physics 2020-07-07 Ivan Agullo , Javier Olmedo , V. Sreenath

We analyze the big bounce transition of the quantum FRW model in the setting of the nonstandard loop quantum cosmology (LQC). Elementary observables are used to quantize compound observables. The spectrum of the energy density operator is…

General Relativity and Quantum Cosmology · Physics 2015-05-20 Wlodzimierz Piechocki

A new mathematical framework is formulated to derive the effective equations of motion for the constrained quantum system which possesses an internal clock. In the realm close to classical behavior, the quantum evolution is approximated by…

General Relativity and Quantum Cosmology · Physics 2008-12-05 Dah-Wei Chiou