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We propose a new cosmological paradigm in which our observed expanding phase is originated from an initially large contracting Universe that subsequently experienced a bounce. This category of models, being geodesically complete, is…

General Relativity and Quantum Cosmology · Physics 2008-11-07 Patrick Peter , Nelson Pinto-Neto

The global dynamics of a homogeneous universe in Loop Quantum Cosmology is viewed as a scattering process of its geometrodynamical equivalent. This picture is applied to build a flexible (easy to generalize) and not restricted just to…

General Relativity and Quantum Cosmology · Physics 2010-04-22 Wojciech Kaminski , Tomasz Pawlowski

The comprehensive formulation for loop quantum cosmology in the spatially flat, isotropic model was recently constructed. In this paper, the methods are extended to the anisotropic Bianchi I cosmology. Both the precursor and the improved…

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

The bouncing evolution of an universe in Loop Quantum Cosmolgy can be described very well by a set of effective equations, involving a function $sin \; x$. Recently, we have generalised these effective equations to $(d + 1)$ dimensions and…

General Relativity and Quantum Cosmology · Physics 2017-08-02 S. Kalyana Rama

It is generally expected that in a non-singular cosmological model a cyclic evolution is straightforward to obtain on introduction of a suitable choice of a scalar field with a negative potential or a negative cosmological constant which…

General Relativity and Quantum Cosmology · Physics 2022-03-14 Bao-Fei Li , Parampreet Singh

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

We study a contracting universe composed of cold dark matter and radiation, and with a positive cosmological constant. As is well known from standard cosmological perturbation theory, under the assumption of initial quantum vacuum…

General Relativity and Quantum Cosmology · Physics 2015-06-23 Yi-Fu Cai , Edward Wilson-Ewing

Loop quantum cosmology (LQC) predicts a nonsingular evolution of the universe through a bounce in the high energy region. But LQC has an ambiguity about the quantization scheme. Recently, the authors in [Phys. Rev. D 77, 124008 (2008)]…

General Relativity and Quantum Cosmology · Physics 2014-11-18 Li-Fang Li , Jian-Yang Zhu

We provide an analytical solution to the quantum dynamics of a flat Friedmann-Lema\^itre- Robertson-Walker model with a massless scalar field in the presence of a small and positive cosmological constant, in the context of Loop Quantum…

General Relativity and Quantum Cosmology · Physics 2020-02-06 Mercedes Martín-Benito , Rita B. Neves

For the Bianchi type I space-time (vacuum or with a massless scalar field), the loop quantum cosmology bounce can be viewed as a rapid transition between two classical solutions, with a simple transformation rule relating the Kasner…

General Relativity and Quantum Cosmology · Physics 2018-03-14 Edward Wilson-Ewing

We study the classical dynamics of black holes during a nonsingular cosmological bounce. Taking a simple model of a nonsingular bouncing cosmology driven by the combination of a ghost and ordinary scalar field, we use nonlinear evolutions…

General Relativity and Quantum Cosmology · Physics 2022-10-03 Maxence Corman , William E. East , Justin L. Ripley

We consider Brans-Dicke cosmology with cosmological constant with negative w parameter and an arbitrary (in general non-vanishing) scale factor at the Big Bang. The field equations describe the flat universe, current observational values…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Darya Tretyakova , Alexander Shatskiy , Igor Novikov , Stanislav Alexeyev

Non-perturbative quantum geometric effects in Loop Quantum Cosmology predict a $\rho^2$ modification to the Friedmann equation at high energies. The quadratic term is negative definite and can lead to generic bounces when the matter energy…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Parampreet Singh , Kevin Vandersloot , G. V. Vereshchagin

It is known that in loop quantum cosmology (LQC) the universe avoids the singularity by a bounce when the matter density approaches the critical density $\rho_c$ (the order of Planck density). After incorporating the inverse volume…

General Relativity and Quantum Cosmology · Physics 2011-03-14 Hua-Hui Xiong , Jian-Yang Zhu

We investigate a particular type of classical nonsingular bouncing cosmology, which results from general relativity if we allow for degenerate metrics. The simplest model has a matter content with a constant equation-of-state parameter and…

General Relativity and Quantum Cosmology · Physics 2019-10-23 F. R. Klinkhamer , Z. L. Wang

The early Cosmology driven by a single scalar field, both massless and massive, in the context of Eddington-inspired Born-Infeld gravity, is explored. We show the existence of nonsingular solutions of bouncing and loitering type (depending…

General Relativity and Quantum Cosmology · Physics 2021-11-15 David Benisty , Gonzalo J. Olmo , Diego Rubiera-Garcia

We present the method of describing an evolution in quantum cosmology in the framework of the reduced phase space quantization of loop cosmology. We apply our method to the flat Friedman-Robertson-Walker model coupled to a massless scalar…

General Relativity and Quantum Cosmology · Physics 2012-03-06 Jakub Mielczarek , Wlodzimierz Piechocki

We investigate the different meanings that the concept of Quantum Bounce acquires in various formalisms. The original idea refers to the phenomenology that appears in the Klein-Gordon framework when homogeneous cosmologies are considered.…

General Relativity and Quantum Cosmology · Physics 2025-12-01 Eleonora Giovannetti

An alternative to the Big Bang cosmologies is obtained by the Big Bounce cosmologies. In this paper, we study a bounce cosmology with a Type IV singularity occurring at the bouncing point, in the context of $F(R)$ modified gravity. We…

General Relativity and Quantum Cosmology · Physics 2017-01-17 S. D. Odintsov , V. K. Oikonomou

Scenario of a bouncing universe is one of the most active area of research to arrive at singularity free cosmological models. Different proposals have been suggested to avoid the so called 'big bang' singularity through the quantum aspect…

General Relativity and Quantum Cosmology · Physics 2022-10-26 Indrani Banerjee , Tanmoy Paul , Soumitra SenGupta