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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

Coherent state functional integral for the minisuperspace model of loop quantum cosmology is studied. By the well-established canonical theory, the transition amplitude in the path integral representation of loop quantum cosmology with…

General Relativity and Quantum Cosmology · Physics 2012-06-07 Li Qin , Yongge Ma

A general nonperturvative loop quantization procedure for metric modified gravity is reviewed. As an example, this procedure is applied to scalar-tensor theories of gravity. The quantum kinematical framework of these theories is rigorously…

General Relativity and Quantum Cosmology · Physics 2013-04-09 Xiangdong Zhang , Yongge Ma

A class of $k$-Essence cosmological models, with a power law kinetic term, is quantised in the mini-superspace. It is shown that for a specific configuration, corresponding to a pressureless fluid, a Schr\"odinger-type equation is obtained…

General Relativity and Quantum Cosmology · Physics 2016-12-28 C. R. Almeida , J. C. Fabris , F. Sbisá , Y. Tavakoli

In this thesis we consider the problem of dynamics in canonical loop quantum gravity, primarily in the context of deparametrized models, in which a scalar field is taken as a physical time variable for the dynamics of the gravitational…

General Relativity and Quantum Cosmology · Physics 2021-01-01 Ilkka Mäkinen

A set of diverse but mutually consistent results obtained in different settings has spawned a new view of loop quantum gravity and its physical implications, based on the interplay of operator calculations and effective theory: Quantum…

General Relativity and Quantum Cosmology · Physics 2012-12-27 Martin Bojowald

A discussion is given of the quantisation of a physical system with finite degrees of freedom subject to a Hamiltonian constraint by treating time as a constrained classical variable interacting with an unconstrained quantum state. This…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Charles Wang

Loop quantum gravity is believed to eliminate singularities such as the big bang and big crunch singularity. This belief is based on studies of so-called loop quantum cosmology which concerns symmetry-reduced models of quantum gravity. In…

General Relativity and Quantum Cosmology · Physics 2017-09-12 Ward Struyve

A semiclassical cosmological model is considered which consists of a closed Friedmann-Robertson-Walker in the presence of a cosmological constant, which mimics the effect of an inflaton field, and a massless, non-conformally coupled quantum…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Esteban Calzetta , Enric Verdaguer

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

In Loop Quantum Gravity mathematically rigorous models of full quantum gravity were proposed. In this paper we study a cosmological sector of one of the models describing quantum gravity with positive cosmological constant coupled to…

General Relativity and Quantum Cosmology · Physics 2022-11-09 Marcin Kisielowski

Quantum cosmology implies corrections to the classical equations of motion which may lead to significant departures from the classical trajectory, especially at high curvature near the big-bang singularity. Corrections could in principle be…

General Relativity and Quantum Cosmology · Physics 2014-09-09 Martin Bojowald , David Simpson

An analytical approach for studying the cosmological scenario with a homogeneous tachyon field within the framework of loop quantum gravity is developed. Our study is based on the semi-classical regime where space time can be approximated…

General Relativity and Quantum Cosmology · Physics 2009-11-11 A. A. Sen

Loop quantum gravity introduces strong non-perturbative modifications to the dynamical equations in the semi-classical regime, which are responsible for various novel effects, including resolution of the classical singularity in a Friedman…

High Energy Physics - Theory · Physics 2007-05-23 Martin Bojowald , Roy Maartens , Parampreet Singh

The Hamiltonian approach to General Relativity is developed similarly to the Wheeler-DeWitt Hamiltonian cosmology, where the cosmological scale factor is treated as a time-like dynamic variable and its canonical momentum is considered as an…

Astrophysics · Physics 2007-05-23 B. M. Barbashov , V. N. Pervushin , V. A. Zinchuk , A. G. Zorin

A brief review of various numerical techniques used in loop quantum cosmology and results is presented. These include the way extensive numerical simulations shed insights on the resolution of classical singularities, resulting in the key…

General Relativity and Quantum Cosmology · Physics 2013-07-11 Parampreet Singh

In the framework of quasi-topological (QT) gravity, we propose a novel model which is characterized by a bounce of the spacetime such that the singularity in standard general relativity can be avoided in both cosmological and black hole…

General Relativity and Quantum Cosmology · Physics 2026-03-05 Yi Ling , Zhangping Yu

The big bounce transition of the quantum FRW model in the setting of loop quantum cosmology is presented. We determine the physical self-adjoint Hamiltonian generating the dynamics. It is used to define, via the Stone theorem, an evolution…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Wlodzimierz Piechocki

We explore the extension of quantum cosmology outside the homogeneous approximation, using the formalism of loop quantum gravity. We introduce a model where some of the inhomogeneous degrees of freedom are present, providing a tool for…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Carlo Rovelli , Francesca Vidotto

We compare the recent loop quantum cosmology approach of Bojowald and co-workers with earlier quantum cosmological schemes. Because the weak-energy condition can now be violated at short distances, and not necessarily with a high energy…

General Relativity and Quantum Cosmology · Physics 2016-08-31 D. H. Coule