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Exploiting the existence of two "cosmological" constants, one associated with the classical Lovelock theorem and one with the vacuum energy density, we argue, in a model independent way, that in spatially closed FLRW cosmologies with a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Benjamin K. Tippett , Kayll Lake

Modeling of matter bounce in $f(R,T)$ gravity has been presented with no violation of the null energy condition. Only a closed universe with negative pressure is allowed in good agreement with some recent observations which favor a universe…

General Relativity and Quantum Cosmology · Physics 2022-06-22 Vinod Kumar Bhardwaj , Anirudh Pradhan , Nasr Ahmed , A. A. Shaker

In this paper, we have presented a bouncing cosmological model of the Universe in an extended theory of gravity. The dynamical behaviour of the model obtained from the flat FLRW space-time along with the violation of null energy condition…

General Relativity and Quantum Cosmology · Physics 2022-04-22 A. S. Agrawal , Francisco Tello-Ortiz , B. Mishra , S. K. Tripathy

Bouncing models have been proposed by many authors as a completion, or even as an alternative to inflation for the description of the very early and dense Universe. However, most bouncing models contain a contracting phase from a very large…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-31 Rodrigo Maier , Stella Pereira , Nelson Pinto-Neto , Beatriz B. Siffert

The current expansion of the Universe has been observed to be accelerating, and the widely accepted spatially-flat concordance model of general relativistic cosmology attributes this phenomenon to a constant dark energy, a cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-13 Shulei Cao

In this work we consider a cosmological scenario in which the Universe contracts initially having a bouncing-like behavior, and accordingly after it bounces off, it decelerates following a matter dominated like evolution and at very large…

General Relativity and Quantum Cosmology · Physics 2020-12-02 S. D. Odintsov , V. K. Oikonomou , Tanmoy Paul

We examine the dynamics of FLRW cosmologies in which the vacuum interacts with a perfect fluid through an energy exchange, focusing on the exploration of nonsingular configurations, including cyclic and bouncing models. We consider two…

General Relativity and Quantum Cosmology · Physics 2022-05-06 Marco Bruni , Rodrigo Maier , David Wands

We investigate a bounce realization in the framework of higher order curvature in $ f(R,T) $ modified theory of gravity. We perform a detailed analysis of the cosmological parameters to explain the contraction phase, the bounce phase, and…

General Relativity and Quantum Cosmology · Physics 2023-07-19 J. K. Singh , Shaily , Akanksha Singh , Aroonkumar Beesham , Hamid Shabani

We investigate the cosmology of a class of model with noncanonical scalar field and matter both in FRW closed and open background. Writing the Einstein Equations in terms of dimensionless dynamical variables suitable for studying bouncing…

General Relativity and Quantum Cosmology · Physics 2015-01-12 Manabendra Sharma

A matter bouncing entropy-corrected cosmological model has been suggested. The model allows only positive curvature with negative pressure and no violation of the null energy condition. The result obtained in this paper is supported by some…

General Relativity and Quantum Cosmology · Physics 2022-10-12 Nasr Ahmed , Tarek M. Kamel , Mohamed I Nouh

We investigate cosmological models with a linear inhomogeneous time-dependent equation of state for the dark energy, coupled with dark matter, leading to a bounce cosmology. Equivalent descriptions in terms of the equation-of-state…

General Relativity and Quantum Cosmology · Physics 2014-05-07 I. Brevik , V. V. Obukhov , A. V. Timoshkin

Analyzing quantum cosmological scenarios containing one scalar field with exponential potential, we have obtained a universe model which realizes a classical dust contraction from very large scales, the initial repeller of the model, and…

General Relativity and Quantum Cosmology · Physics 2017-09-13 Samuel Colin , Nelson Pinto-Neto

A new class of FLRW cosmological models with time-evolving fundamental parameters should emerge naturally from a description of the expansion of the universe based on the first principles of quantum field theory and string theory. Within…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-09 Javier Grande , Joan Sola , Spyros Basilakos , Manolis Plionis

Among many models which can describe the bouncing cosmology, A matter bounce scenario that is deformed by a running vacuum model of dark energy (RVM-DE) has been interested. In this research, I show that a class of RVM-CDM (cold dark…

General Relativity and Quantum Cosmology · Physics 2022-09-13 A. Khodam-Mohammadi

We investigate cosmological scenarios containing one canonical scalar field with an exponential potential in the context of bouncing models, where the bounce happens due to quantum cosmological effects. The only possible bouncing solutions…

General Relativity and Quantum Cosmology · Physics 2018-05-01 Anna Paula Bacalhau , Nelson Pinto-Neto , Sandro Dias Pinto Vitenti

We review the general features of nonsingular universes ({\em i.e.} those that go from an era of accelerated collapse to an expanding era without displaying a singularity) as well as cyclic universes. We discuss the mechanisms behind the…

Astrophysics · Physics 2008-12-18 M. Novello , S. E. Perez Bergliaffa

We revisit a cosmological model where dark matter (DM) and dark energy (DE) follow barotropic equations of state, allowing deviations from the standard $\Lambda$CDM framework (i.e. $w_{dm} \neq 0$, $w_{de} \neq -1$), considering both flat…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-24 Dorian Araya , Cristian Castillo , Genly Leon , Juan Magaña , Angie Barr Domínguez , Miguel A. García-Aspeitia

We review matter bounce scenarios where the matter content is dark matter and dark energy. These cosmologies predict a nearly scale-invariant power spectrum with a slightly red tilt for scalar perturbations and a small tensor-to-scalar…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-28 Yi-Fu Cai , Antonino Marciano , Dong-Gang Wang , Edward Wilson-Ewing

We investigate the dynamics of the FLRW flat cosmological models in which the vacuum energy varies with redshift. A particularly well motivated model of this type is the so-called quantum field vacuum, in which both kind of terms $H^{2}$…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-15 Spyros Basilakos

The singularity and inflationary problems have posed significant challenges for understanding the universe's origin and evolution. Bouncing cosmology has emerged as a promising alternative to standard cosmological models, offering a…

General Relativity and Quantum Cosmology · Physics 2025-07-28 A. Zhadyranova , M. Koussour , V. Zhumabekova , N. Zhusupova , S. Muminov , J. Rayimbaev
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