Effect of an external interaction mechanism in solving agegraphic dark energy problems

Aghamohammadi, Amir; Saaidi, Kh.; Mohammadi, Abolhassan; Sheikhahmadi, Haidar; Golanbari, T.; Rabiei, S. W.

doi:10.1007/s10509-013-1386-5

Cited by 17 publications

(13 citation statements)

References 56 publications

(40 reference statements)

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“…There are many studies on this topic such as [184][185][186][187][188][189][190][191][192], where the authors explain that there are two definitions for the Lagrangian of a perfect fluid as L (2) m = p, respectively. However, in our case, this degeneracy is broken due to the non-minimal interaction of the scalar field and matter, and therefore we follow the approach proposed in [192], where it is shown that only for L (2) m = p one has a geodesic motion for perfect fluids.…”

Section: )mentioning

confidence: 99%

Constraining chameleon field driven warm inflation with Planck 2018 data

et al. 2019

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We investigate warm inflationary scenario in which the accelerated expansion of the early Universe is driven by chameleon-like scalar fields. Due to the non-minimal coupling between the scalar field and the matter sector, the energy-momentum tensor of each fluid component is not conserved anymore, and the generalized balance equation is obtained. The new source term in the energy equation can be used to model warm inflation. On the other hand, if the coupling function varies slowly, the model reduces to the standard model used for the description of cold inflation. To test the validity of the warm chameleon inflation model, the results for warm inflationary scenarios are compared with the observational Planck2018 Cosmic Microwave Background data. In this regard, the perturbation parameters such as the amplitude of scalar perturbations, the scalar spectral index and the tensor-to-scalar ratio are derived at the horizon crossing in two approximations, corresponding to the weak and strong dissipative regimes. As a general result it turns out that the theoretical predictions of the chameleon warm inflationary scenario are consistent with the Planck 2018 observations.

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Section: )mentioning

confidence: 99%

Constraining chameleon field driven warm inflation with Planck 2018 data

et al. 2019

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“…ordinary cosmic time, t. As mentioned in the introduction, the Lagrangian of the matter is considered to verify L = L (m) + L (de) , [52,54], where the subscript m denotes matter (cold dark matter and baryons) and de refers to dark energy. Then the conservation equations could be rewritten as…”

Section: Conservation and Field's Equations In An Effective Dark Enermentioning

confidence: 99%

“…Also it is notable, if we choose β = 0, that the model reduces to EoS constant models (for instance C DM) [54]. By substituting (36) in (30), the dimensionless Hubble parameter is obtained as follows:…”

Section: Deceleration Parametermentioning

confidence: 99%

Interacting scalar tensor cosmology in light of SNeIa, CMB, BAO and OHD observational data sets

et al. 2016

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In this work, an interacting chameleon-like scalar field scenario, by considering SNeIa, CMB, BAO, and OHD data sets, is investigated. In fact, the investigation is realized by introducing an ansatz for the effective dark energy equation of state, which mimics the behavior of chameleonlike models. Based on this assumption, some cosmological parameters, including the Hubble, deceleration, and coincidence parameters, in such a mechanism are analyzed. It is realized that, to estimate the free parameters of a theoretical model, by regarding the systematic errors it is better that the whole of the above observational data sets would be considered. In fact, if one considers SNeIa, CMB, and BAO, but disregards OHD, it maybe leads to different results. Also, to get a better overlap between the contours with the constraint χ 2 m ≤ 1, the χ 2 T function could be re-weighted. The relative probability functions are plotted for marginalized likelihood L ( m0 , ω 1 , β) according to the two dimensional confidence levels 68.3, 90, and 95.4 %. Meanwhile, the value of the free parameters which maximize the marginalized likelihoods using the above confidence levels are obtained. In addition, based on these calculations the minimum value of χ 2 based on the free parameters of the ansatz for the effective dark energy equation of state is achieved.

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“…Amongst such parameters one can mention scalar spectral index n s , tensor spectral index n T and the tensor-to-scalar ratio r. From Eqs. (41) and (42), ρ s can be attained as…”

Section: Chaotic Inflationmentioning

confidence: 99%

Non-local scalar fields inflationary mechanism in light of Planck 2013

Sheikhahmadi

Ghorbani

Saaidi

2015

Astrophys Space Sci

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A generalization of the canonical and non-canonical theory of inflation is introduced in which the kinetic energy term in action is written as non-local term. The inflationary universe within the framework of considering this non-locality will be studied. To investigate the effects of non-locality on the inflationary parameters we consider two well known models of inflationary scenario includes of chaotic and exponential inflation proposals. For such scenarios some important parameters include slow roll parameters, scalar and tensor power spectra, spectral indices, the tensor-to-scalar ratio and so on for both mentioned models, chaotic and exponential inflationary scenarios, will be calculated. Also the Hamilton-Jacobi formalism, as an easiest way to study the effect of perturbation based on e-folding number N , to investigate inflationary attractors will be used. The free theoretical parameters of this model will be compared with observations by means of Planck 2013, W M AP 9 + eCM B + BAO + H 0 data sets in addition to BICEP 2 data surveying. It will be shown that our theoretical results are in acceptable range in comparison to observations. For instance the tensor-to-scalar ratio for exponential potential, by considering BICEP 2 is in best agreement in comparison with chaotic inflation.

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Effect of an external interaction mechanism in solving agegraphic dark energy problems

Cited by 17 publications

References 56 publications

Constraining chameleon field driven warm inflation with Planck 2018 data

Constraining chameleon field driven warm inflation with Planck 2018 data

Interacting scalar tensor cosmology in light of SNeIa, CMB, BAO and OHD observational data sets

Non-local scalar fields inflationary mechanism in light of Planck 2013

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