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An one-parameter regularization freedom of the Hamiltonian constraint for loop quantum gravity is analyzed. The corresponding spatially flat, homogenous and isotropic model includes the two well-known models of loop quantum cosmology as…

General Relativity and Quantum Cosmology · Physics 2021-11-12 Xiangdong Zhang , Gaoping Long , Yongge Ma

This is the first paper of a series dedicated to LQG coherent states and cosmology. The concept is based on the effective dynamics program of Loop Quantum Cosmology, where the classical dynamics generated by the expectation value of the…

General Relativity and Quantum Cosmology · Physics 2019-11-14 Andrea Dapor , Klaus Liegener

Coherent state functional integrals for the minisuperspace models of quantum cosmology are studied. By the well-established canonical theories, the transition amplitudes in the path-integral representations of Wheeler-DeWitt quantum…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Li Qin , Yongge Ma

Within a perturbative cosmological regime of loop quantum gravity corrections to effective constraints are computed. This takes into account all inhomogeneous degrees of freedom relevant for scalar metric modes around flat space and results…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Hector Hernandez , Mikhail Kagan , Aureliano Skirzewski

It has been suggested that the homogeneous black hole interior spacetime, when quantized following the techniques of loop quantum cosmology, has a resolved singularity replaced by a black-to-white hole transition. This result has however…

General Relativity and Quantum Cosmology · Physics 2021-03-23 Francesco Sartini , Marc Geiller

Recently the mechanism was found which allows avoidance of the cosmological singularity within the semi-classical formulation of Loop Quantum Gravity. Numerical studies show that the presence of self-interaction potential of the scalar…

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

The big bang singularity could be understood as a breakdown of Einstein's General Relativity at very high energies. Adopting this viewpoint, other theories, that implement Einstein Cosmology at high energies, might solve the problem of the…

General Relativity and Quantum Cosmology · Physics 2015-06-15 Jaume Amorós , Jaume de Haro , Sergei D. Odintsov

The goal of spin foam models is to provide a viable path integral formulation of quantum gravity. Because of background independence, their underlying framework has certain novel features that are not shared by path integral formulations of…

General Relativity and Quantum Cosmology · Physics 2011-01-25 Abhay Ashtekar , Miguel Campiglia , Adam Henderson

With a well-motivated extension of higher order holonomy corrections, the quantum theory of loop quantum cosmology (LQC) for the $k=0$ Friedmann-Robertson-Walker model (with a free massless scalar) is rigorously formulated. The analytical…

General Relativity and Quantum Cosmology · Physics 2009-08-18 Dah-Wei Chiou , Li-Fang Li

We consider the loop quantum theory of the spherically symmetric model of gravity coupled to Gaussian dust fields, where the Gaussian dust fields provide a material reference frame of the space and time to deparameterize gravity. This…

General Relativity and Quantum Cosmology · Physics 2022-02-25 Cong Zhang

Effective equations are often useful to extract physical information from quantum theories without having to face all technical and conceptual difficulties. One can then describe aspects of the quantum system by equations of classical type,…

High Energy Physics - Theory · Physics 2008-11-26 Martin Bojowald , Aureliano Skirzewski

A coarse graining technique akin to block spin transformations that groups together fiducial cells in a homogeneous and isotropic universe has been recently developed in the context of loop quantum cosmology. The key technical ingredient…

General Relativity and Quantum Cosmology · Physics 2021-06-30 Norbert Bodendorfer , Muxin Han , Fabian Haneder , Hongguang Liu

This papers offers a critical discussion on the procedure by which Loop Quantum Cosmology (LQC) is constructed from the full Loop Quantum Gravity (LQG) theory. Revising recent issues in preserving SU(2) symmetry when quantizing the…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Francesco Cianfrani , Giovanni Montani

Loop quantum cosmology predicts that quantum gravity effects resolve the big-bang singularity and replace it by a cosmic bounce. Furthermore, loop quantum cosmology can also modify the form of primordial cosmological perturbations, for…

General Relativity and Quantum Cosmology · Physics 2017-06-28 Edward Wilson-Ewing

The fundamental theory and the semiclassical description of loop quantum cosmology (LQC) have been studied in the Friedmann-Robertson-Walker and Bianchi I models. As an extension to include both anisotropy and intrinsic curvature, this…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Dah-Wei Chiou

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

We study the path integral formulation of Friedmann universe filled with a massless scalar field in loop quantum cosmology. All the isotropic models of $k=0,+1,-1$ are considered. To construct the path integrals in the timeless framework, a…

General Relativity and Quantum Cosmology · Physics 2011-06-28 Haiyun Huang , Yongge Ma , Li Qin

Covariant Loop Quantum Gravity (CLQG) is a tentative background-independent and non-perturbative theory of quantum gravity which has emerged from a number of different research directions. Recently, this theory has been applied to the…

General Relativity and Quantum Cosmology · Physics 2020-01-15 Fabio D'Ambrosio

In the last 20 years, loop quantum gravity, a background independent approach to unify general relativity and quantum mechanics, has been widely investigated. The aim of loop quantum gravity is to construct a mathematically rigorous,…

General Relativity and Quantum Cosmology · Physics 2007-06-25 Muxin Han

The existence of a quantum bounce in isotropic spacetimes is a key result in loop quantum cosmology (LQC), which has been demonstrated to arise in all the models studied so far. In most of the models, the bounce has been studied using…

General Relativity and Quantum Cosmology · Physics 2017-06-20 Peter Diener , Brajesh Gupt , Parampreet Singh