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We consider the oscillating dark energy with periodic equation of state in two equivalent formulations: ideal fluid or scalar-tensor theory. It is shown that such dark energy suggests the natural way for the unification of early-time…

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

In this paper, we study damped oscillating form of dark energy for explaining dynamics of universe. First of all, we consider universe is filled with an ideal fluid which has damped oscillating dark energy in terms of this case we calculate…

General Relativity and Quantum Cosmology · Physics 2015-08-13 Nilay Bostan , Ekrem Aydiner

An oscillating, homogeneous and isotropic Universe which arises from Scalar-Tensor gravity is discussed in the linearized approach, showing that some observative evidences like the Hubble Law and the Cosmological Redshift are in agreement…

Astrophysics · Physics 2010-01-24 Christian Corda

The concept of oscillatory Universe appears to be realistic and buried in the dynamic dark energy equation of state. We explore its evolutionary history under the frame work of general relativity. We observe that oscillations do not go…

General Physics · Physics 2013-03-15 Partha Pratim Ghosh , Saibal Ray , A. A. Usmani , Utpal Mukhopadhyay

The dark energy universe equation of state (EOS) with inhomogeneous,Hubble parameter dependent term is considered. The motivation to introduce such a term comes from time-dependent viscosity considerations and modifications of general…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

Current observations seem to mildly favor an evolving dark energy with the equation of state getting across -1. This form of dark energy, dubbed Quintom, is studied phenomenologically in this paper with an oscillating equation of state. We…

Astrophysics · Physics 2008-11-26 Bo Feng , Mingzhe Li , Yun-Song Piao , Xinmin Zhang

The four-dimensional Friedman flat universe, filled with an ideal fluid with a linear (oscillating) inhomogeneous equation of state (EoS) depending on time, is studied. The equations of motion are solved. It is shown that in some cases…

General Relativity and Quantum Cosmology · Physics 2008-11-26 I. Brevik , O. G. Gorbunova , A. V. Timoshkin

The accelerating Friedmann flat universe, filled with an ideal fluid with a linear (oscillating) inhomogeneous equation of state (EoS) depending on time, is reviewed. The equations of motions are solved. It is shown that in some cases there…

General Relativity and Quantum Cosmology · Physics 2009-03-10 O. G. Gorbunova , A. V. Timoshkin

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

The purpose of this short review is to describe cosmological models with a linear inhomogeneous time-dependent equation of state (EoS) for the dark energy, when the dark fluid is coupled with dark matter. This may lead to a bounce…

General Relativity and Quantum Cosmology · Physics 2015-03-17 Iver Brevik , Alexander Timoshkin

In this study we consider an exponential decaying form for dark energy as EoS parameter in order to discuss the dynamics of the universe. Firstly, assuming that universe is filled with an ideal fluid which consists of exponential decaying…

General Relativity and Quantum Cosmology · Physics 2015-08-13 Nilay Bostan , Ekrem Aydiner

We analyze an oscillating universe model in brane world scenario. The oscillating universe cycles through a series of expansions and contractions and its energy density is dominated by dust matter at early-time expansion phase and by…

Astrophysics · Physics 2009-11-13 Guangcan Yang , Anzhong Wang

An oscillating Universe which arises from the linearized R^{2} theory of gravity is discussed, showing that some observative evidences like the cosmological redshift and the Hubble law are in agreement with the model. In this context Dark…

Astrophysics · Physics 2009-06-23 Christian Corda

Coherent oscillations of a scalar field can mimic the behavior of a perfect fluid with an equation-of-state parameter determined by the properties of the potential, possibly driving accelerated expansion in the early Universe (inflation)…

Astrophysics · Physics 2009-02-23 Matthew C. Johnson , Marc Kamionkowski

We investigate the validity of cosmological models with an oscillating scale factor in relation to late-time cosmological observations. We show that these models not only meet the required late time observational constraints but can also…

General Relativity and Quantum Cosmology · Physics 2023-05-31 Mohit K. Sharma , Shibesh Kumar Jas Pacif , Gulmira Yergaliyeva , Kuralay Yesmakhanova

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

We investigate homogeneous and isotropic oscillating cosmologies with multiple fluid components. Transfer of energy between these fluids is included in order to model the effects of non-equilibrium behavior on closed universes. We find…

General Relativity and Quantum Cosmology · Physics 2008-11-26 T. Clifton , John D. Barrow

We analyse the universe homogeneously filled up by different dark energies. We calculate the relations between time and the scale factor. We thoroughly check the differences to be obtained with the changes of different parameters. $t$ vs…

General Relativity and Quantum Cosmology · Physics 2018-07-26 Promila Biswas , Ritabrata Biswas

Multiacceleration scenario can be used to solve the cosmological coincidence problem. In this paper, after considering the early radiation era, we revisit the cosmological dynamics of the oscillating dark energy model proposed in…

General Relativity and Quantum Cosmology · Physics 2020-10-08 S. X. Tian

An oscillating universe cycles through a series of expansions and contractions. We propose a model in which ``phantom'' energy with $p < -\rho$ grows rapidly and dominates the late-time expanding phase. The universe's energy density is so…

Astrophysics · Physics 2014-10-13 Matthew G. Brown , Katherine Freese , William H. Kinney
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