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We analyze the semiclassical polymer dynamics of the inhomogeneous Mixmaster model by choosing the cubed scale factor as the discretized configurational variable, while the anisotropies remain pure Einsteinian variables. Such a modified…

General Relativity and Quantum Cosmology · Physics 2019-02-06 Stefano Antonini , Giovanni Montani

This work investigates a singularity-free early Universe within the paradigm of quantum cosmology. We develop a bouncing model where the singularity is resolved via the de Broglie--Bohm interpretation of quantum mechanics, which provides a…

General Relativity and Quantum Cosmology · Physics 2026-02-24 Micol Benetti , Rudnei O. Ramos , Renato Silva , Gustavo S. Vicente

The Planck collaboration has provided us rich information about the early universe, and a host of new observational missions will soon shed further light on the `anomalies' that appear to exist on the largest angular scales. From a quantum…

General Relativity and Quantum Cosmology · Physics 2015-11-18 Abhay Ashtekar , Aurelien Barrau

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

The quantum nature of the Big Bang is reexamined in the framework of Loop Quantum Cosmology. The strict application of a regularization procedure to the Hamiltonian, originally developed for the Hamiltonian in loop quantum gravity, leads to…

General Relativity and Quantum Cosmology · Physics 2018-08-29 Mehdi Assanioussi , Andrea Dapor , Klaus Liegener , Tomasz Pawłowski

We consider a phenomenological modification of the Pre Big Bang scenario using ideas from the resolution of curvature singularities in Loop Quantum Cosmology. We show that non-perturbative Loop modifications to the dynamics, arising from…

High Energy Physics - Theory · Physics 2008-11-26 Giuseppe De Risi , Roy Maartens , Parampreet Singh

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

Loop quantum cosmology applies techniques derived for a background independent quantization of general relativity to cosmological situations and draws conclusions for the very early universe. Direct implications for the singularity problem…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Martin Bojowald

We present a review on basic aspects of quantum cosmology in the presence of cut-off physics. We first analyze how the Wheeler-DeWitt equation in a pure metric approach describes the quantum Universe, showing how the singularity is not…

General Relativity and Quantum Cosmology · Physics 2021-09-20 Gabriele Barca , Eleonora Giovannetti , Giovanni Montani

A Quintom universe with an equation-of-state crossing the cosmological constant boundary can provide a bouncing solution dubbed the Quintom Bounce and thus resolve the Big Bang singularity. In this paper, we investigate the cosmological…

High Energy Physics - Theory · Physics 2008-11-26 Yi-Fu Cai , Taotao Qiu , Robert Brandenberger , Yun-Song Piao , Xinmin Zhang

Assignment of consistent quantum probabilities to events in a quantum universe is a fundamental challenge which every quantum cosmology/gravity framework must overcome. In loop quantum cosmology, this issue leads to a fundamental question:…

General Relativity and Quantum Cosmology · Physics 2016-04-01 David Craig , Parampreet Singh

We investigate the emergence of a quantum Big-Bounce in the context of an isotropic Universe, filled by a self-interacting scalar field, which plays the role of a physical clock. The bouncing cosmology is the result of a scattering process,…

General Relativity and Quantum Cosmology · Physics 2024-10-04 S. Lo Franco , G. Montani

We point out that the relative Heisenberg uncertainty relations vanish for non-compact spaces in homogeneous loop quantum cosmology. As a consequence, for sharply peaked states quantum fluctuations in the scale factor never become…

General Relativity and Quantum Cosmology · Physics 2015-06-17 Carlo Rovelli , Edward Wilson-Ewing

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

According to the Belinskii-Khalatnikov-Lifshitz scenario, a collapsing universe approaching a spacelike singularity can be approximated by homogeneous cosmological dynamics, but only if asymptotically small spatial regions are considered.…

General Relativity and Quantum Cosmology · Physics 2020-07-16 Martin Bojowald

The loop quantization of the negatively curved k=-1 RW model poses several technical challenges. We show that the issues can be overcome and a successful quantization is possible that extends the results of the k=0,+1 models in a natural…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Kevin Vandersloot

In this paper, a new Hamiltonian constraint operator for loop quantum cosmology is constructed by using the Chern-Simons action. The quantum dynamics of the $k=0$ cosmological model with respect to a massless scalar field as an emergent…

General Relativity and Quantum Cosmology · Physics 2019-09-23 Jinsong Yang , Cong Zhang , Yongge Ma

We review the classical and quantum singularity structure of a broad class of spacetimes with asymptotically power-law behavior near the origin. Quantum considerations "heal" a large class of scalar curvature singularities.

General Relativity and Quantum Cosmology · Physics 2010-06-21 D. A. Konkowski , T. M. Helliwell

The question of possible physics before Big Bang (or after Big Crunch) is addressed via a schematic non-covariant simulation of the loss of observability of the Universe. Our model is drastically simplified by the reduction of its degrees…

General Relativity and Quantum Cosmology · Physics 2012-02-21 Miloslav Znojil

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