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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

In the present work, flat FRW model of the universe is considered to be an isolated open thermodynamical system where non-equilibrium prescription has been studied using the mechanism of particle creation. In the perspective of recent…

General Physics · Physics 2016-05-17 Subhajit Saha , Atreyee Biswas , Subenoy Chakraborty

The matter creation model of Prigogine--G\'eh\'eniau--Gunzig--Nardone is revisited in terms of a redefined creation pressure which does not lead to irreversible adiabatic evolution at constant specific entropy. With the resulting freedom to…

General Relativity and Quantum Cosmology · Physics 2022-09-15 Rossen I. Ivanov , Emil M. Prodanov

We propose that the size of the universe and its rate of expansion cannot be simultaneously specified with arbitrary precision, a quantum mechanical statement encoded in a deformed commutation relation for the scale factor. The deformation…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-15 Savvas M. Koushiappas

In this paper, the dynamical behavior of the accelerated expansion of the universe is studied within the framework of $f(T)$ gravity by considering a well-motivated functional form of $f(T)$. A specific form of the Hubble parameter is…

General Relativity and Quantum Cosmology · Physics 2026-03-20 Khomesh R. Patle , G. P. Singh

In this work we present the cosmological dynamics of interacting dark energy models in the framework of particle creation mechanism. The particle creation mechanism presented here describes the true non equilibrium thermodynamics of the…

General Relativity and Quantum Cosmology · Physics 2017-06-07 Sujay Kr. Biswas , Wompherdeiki Khyllep , Jibitesh Dutta , Subenoy Chakraborty

The energy conditions provide a very promising model-independent study of the current acceleration of the universe. However, in order to connect these conditions with observations, one often needs first to integrate them, and then find the…

Astrophysics · Physics 2009-06-23 Yungui Gong , Anzhong Wang

A new kind of accelerating flat model with no dark energy that is fully dominated by cold dark matter (CDM) is investigated. The number of CDM particles is not conserved and the present accelerating stage is a consequence of the negative…

Astrophysics · Physics 2014-11-18 J. A. S. Lima , F. E. Silva , R. C. Santos

The creation of ultra-light dark particles in the late-time FLRW spacetime provides a cosmological model in accordance with precise observational tests. The matter creation backreaction implies in this context a vacuum energy density…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-11 Saulo Carneiro

A bouncing cosmology with an initial matter-dominated phase of contraction during which scales which are currently probed with cosmological observations exit the Hubble radius provides a mechanism alternative to inflation for producing a…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-20 Robert H. Brandenberger

Recent observations suggest that Hubble's constant is large, and hence that the Universe appears to be younger than some of its constituents. The traditional escape route, which assumes that the expansion is accelerating, appears to be…

Astrophysics · Physics 2009-11-07 J. C. Jackson , Marina Dodgson

In the present lore of cosmology, matter and space-time emerged from a singularity and evolved through four different regimes: inflation, radiation, dark matter and dark energy dominated eras. In the radiation and dark matter dominated…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-13 J. A. S. Lima , S. Basilakos

Understanding the evolution of dark energy poses a significant challenge in modern cosmology, as it is responsible for the universe's accelerated expansion. In this study, we focus on a specific $f(T)$ cosmological model and analyze its…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-14 A. Zhadyranova , M. Koussour , S. Bekkhozhayev , V. Zhumabekova , J. Rayimbaev

Combining intervals of ekpyrotic (ultra-slow) contraction with a (non-singular) classical bounce naturally leads to a novel cyclic theory of the universe in which the Hubble parameter, energy density and temperature oscillate periodically,…

General Relativity and Quantum Cosmology · Physics 2019-07-12 Anna Ijjas , Paul J. Steinhardt

In this paper, a general entropy-corrected FRW cosmological model has been presented in which a deceleration-to-acceleration transition occurs according to recent observations. We found that the case for the flat universe ($k=0$), supported…

General Relativity and Quantum Cosmology · Physics 2019-10-23 Nasr Ahmed , Sultan Z. Alamri

We study cosmological evolution in a flat FLRW spacetime in the context of modified STEGR gravity or $f(Q)$, using an exponential two-parameter model which represents a smooth perturbative expansion around the $\Lambda$CDM model. The…

General Relativity and Quantum Cosmology · Physics 2025-04-15 Ivan R. Vasquez , A. Oliveros

Large-scale peculiar motions are believed to reflect the local inhomogeneity and anisotropy of the universe, triggered by the ongoing process of structure formation. As a result, realistic observers do not follow the smooth Hubble flow but…

General Relativity and Quantum Cosmology · Physics 2015-09-23 Christos G. Tsagas , Miltiadis I. Kadiltzoglou

We investigate a fourth order model of gravity, having a free length parameter, and no cosmological constant or dark energy. We consider cosmological evolution of a flat Friedmann universe in this model for the case that the length…

General Relativity and Quantum Cosmology · Physics 2015-10-14 Shreya Banerjee , Nilesh Jayswal , Tejinder P. Singh

Observations of the cosmic microwave sky are revealing the primordial non-uniformities from which all structure in the Universe grew. The only known physical mechanism for generating the inhomogeneities we see involves the amplification of…

Astrophysics · Physics 2009-10-31 Neil Turok

We investigate a cosmological model in which dark energy identified with the vacuum energy which is running and decaying. In this model vacuum is metastable and decays into a bare (true) vacuum. This decaying process has a quantum nature…

General Relativity and Quantum Cosmology · Physics 2020-04-29 Marek Szydlowski , Aleksander Stachowski , Krzysztof Urbanowski
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