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Inspired by the entropy-area relation of black hole thermodynamics, we study the thermodynamics of cosmological apparent horizon in a spatially flat Friedmann-Robertson-Walker (FRW) universe in the framework of an Extended Uncertainty…

General Relativity and Quantum Cosmology · Physics 2024-08-29 Maryam Roushan , Narges Rashidi , Kourosh Nozari

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

Singularity theorems demonstrate the inevitable breakdown of the concept of continuous, classical spacetime under highly general conditions. Quantum gravity is expected to intervene to avoid singularities and models so far hint towards…

General Relativity and Quantum Cosmology · Physics 2024-08-30 Raúl Carballo-Rubio , Stefano Liberati , Vania Vellucci

The primordial Universe can be used as a laboratory to set constraints on quantum gravity. In the framework of Loop Quantum Cosmology, we show that such a proposal for quantum gravity not only solves for the big bang singularity issue but…

General Relativity and Quantum Cosmology · Physics 2012-06-08 Julien Grain

The improved dynamics of loop quantum cosmology is extended to include the Bianchi type II model. Because these space-times admit both anisotropies and non-zero spatial curvature, certain technical difficulties arise over and above those…

General Relativity and Quantum Cosmology · Physics 2010-01-07 Abhay Ashtekar , Edward Wilson-Ewing

We investigate the future evolution of the dark energy universe in modified gravities including $F(R)$ gravity, string-inspired scalar-Gauss-Bonnet and modified Gauss-Bonnet ones, and ideal fluid with the inhomogeneous equation of state…

High Energy Physics - Theory · Physics 2009-09-17 Kazuharu Bamba , Shin'ichi Nojiri , Sergei D. Odintsov

In this paper it is studied the cosmology of a homogeneous and isotropic spacetime endorsed with a conformally coupled massless scalar field. We find six different solutions of the Friedmann equation that represent six different types of…

General Relativity and Quantum Cosmology · Physics 2017-09-20 Salvador J. Robles-Perez

We study spherical charged black holes in the presence of a cosmological constant with corrections motivated by the theory of loop quantum gravity. The effective theory is constructed at the Hamiltonian level by introducing certain…

General Relativity and Quantum Cosmology · Physics 2023-04-12 Asier Alonso-Bardaji , David Brizuela , Raül Vera

The quantum evolution equation of Loop Quantum Cosmology (LQC) -- the quantum Hamiltonian constraint -- is a difference equation. We relate the LQC constraint equation in vacuum Bianchi I separable (locally rotationally symmetric) models…

General Relativity and Quantum Cosmology · Physics 2013-01-25 Christine C. Dantas

In this paper we have investigated some rip cosmological models in an extended symmetric teleparallel gravity theory. We consider the form $f(Q,T)=aQ^m+bT$ in the Einstein-Hilbert action and expressed the field equations and the dynamical…

General Relativity and Quantum Cosmology · Physics 2021-12-28 Laxmipriya Pati , S. A. Kadam , S. K. Tripathy , B. Mishra

We present a new cosmological event, which we named the little sibling of the big rip. This event is much smoother than the big rip singularity. When the little sibling of the big rip is reached, the Hubble rate and the scale factor blow up…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Mariam Bouhmadi-Lopez , Ahmed Errahmani , Prado Martin-Moruno , Taoufik Ouali , Yaser Tavakoli

In this work we shall investigate the occurrence of future cosmological finite-time singularities in the dynamical system corresponding to two cosmological theories, namely that of vacuum $f(R)$ gravity and that of three fluids. The vacuum…

General Relativity and Quantum Cosmology · Physics 2018-08-01 S. D. Odintsov , V. K. Oikonomou

We discuss exotic singularities in the evolution of the universe motivated by the progress of observations in cosmology. Among them there are: Big-Rip (BR), Sudden Future Singularities (SFS), Generalized Sudden Future Singularities (GSFS),…

General Relativity and Quantum Cosmology · Physics 2016-11-15 Mariusz P. Dabrowski , Adam Balcerzak

The knowledge of the universe future is of fundamental importance for any advanced civilization. We study the future of singular dark universe where thermal effects due to the Hawking radiation on the apparent horizon of the FRW universe…

General Relativity and Quantum Cosmology · Physics 2020-07-27 Shin'ichi Nojiri , Sergei D. Odintsov

This work is an analytical study of the main differences between classical inflationary effects of a fast-roll regime and imprints of hybrid Loop Quantum Cosmology (LQC) on the primordial power spectrum. Effective LQC solutions of…

General Relativity and Quantum Cosmology · Physics 2021-10-01 Beatriz Elizaga Navascués , Guillermo A. Mena Marugán

The detailed formulation of loop quantum cosmology with higher order holonomy corrections has been constructed recently in the homogeneous and isotropic spacetime, yet it is important to extend the higher order holonomy corrections to…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Xiao-Jun Yue , Jian-Yang Zhu

We investigate models of future finite-time singularities in $f(T)$ theory, where $T$ is the torsion scalar. The algebraic function $f(T)$ is put as the teleparallel term $T$ plus an arbitrary function $g(T)$. A suitable expression of the…

General Relativity and Quantum Cosmology · Physics 2013-03-26 M. R. Setare , M. J. S. Houndjo

Future singularities arising in a family of models for the expanding Universe, characterized by sharing a convenient parametrization of the energy budget in terms of the deceleration parameter, are classified. Finite-time future…

General Relativity and Quantum Cosmology · Physics 2019-01-23 Emilio Elizalde , Martiros Khurshudyan , Shin'ichi Nojiri

The discrete quantum geometric effects play an important role in dynamical evolution in the loop quantum cosmology. These effects which are significant at the high energies lead to the quadratic energy density modifications to the Friedmann…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Parampreet Singh

A specific loop quantum cosmology model, mLQC-I, motivated by Thiemann's regularization of the Hamiltonian constraint, leads to the resolution of the big bang singularity and bounce in the isotropic setting, in which either the pre-bounce…

General Relativity and Quantum Cosmology · Physics 2026-03-24 Meysam Motaharfar , Parampreet Singh