Om diagnostic applied to scalar field models and slowing down of cosmic acceleration

Shahalam, M.; Sami, Sasha; Agarwal, Abhineet

doi:10.1093/mnras/stv083

Cited by 60 publications

(31 citation statements)

References 75 publications

(76 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both the models have positive curvature however they lie in the quintessence regime. This is an important result as in the literature, its not possible to have positive curvature for quintessence [60].…”

Section: Resultssupporting

confidence: 55%

See 1 more Smart Citation

Cosmic acceleration from coupling of baryonic and dark matter components: Analysis and diagnostics

Agarwal

Myrzakulov

Pacif

et al. 2019

Int. J. Mod. Phys. D

Self Cite

View full text Add to dashboard Cite

In this paper, we examine a scenario in which late-time cosmic acceleration might arise due to the coupling between baryonic matter and dark matter without the presence of extra degrees of freedom. In this case, one can obtain late-time acceleration in Jordan frame and not in Einstein frame. We consider two different forms of parametrization of the coupling function, and put constraints on the model parameters by using an integrated datasets of Hubble parameter, Type Ia supernova and baryon acoustic oscillations. The models under consideration are consistent with the observations. In addition, we perform the statefinder and Om diagnostics, and show that the models exhibit a distinctive behavior due to the phantom characteristic in future which is a generic feature of the underlying scenario.

show abstract

Section: Resultssupporting

confidence: 55%

“…The Om diagnostic also differentiates various DE models from ΛCDM [60]. This is a simpler diagnostic when applied to observations as it depends only on the first derivative of scale factor.…”

Section: Om Diagnosticmentioning

confidence: 99%

Cosmic acceleration from coupling of baryonic and dark matter components: Analysis and diagnostics

Agarwal

Myrzakulov

Pacif

et al. 2019

Int. J. Mod. Phys. D

Self Cite

View full text Add to dashboard Cite

show abstract

“…Thus, for any cosmological model, any deviation of Om(z) from Ω m0 actually signals the difference of the toy model from the base ΛCDM cosmological model. In addition to that, the Om diagnostic also offers a characterization of the dark energy models whether they belong to the quintessence class or the phantom class [111,112,113,114]. Now, in order to understand the evolutions of Om(z) for the scalar field models, we have numerically solved the Hubble function for each scalar field model and present the variations of Om(z) in Fig.…”

Section: Geometrical Test: the Om Diagnosticmentioning

confidence: 99%

Constraints on quintessence scalar field models using cosmological observations

Yang

Shahalam

Pal³

et al. 2019

Phys. Rev. D

Self Cite

View full text Add to dashboard Cite

We consider a varieties of quintessence scalar field models in a homogeneous and isotropic geometry of the universe with zero spatial curvature aiming to provide stringent constraints using a series of cosmological data sets, namely, the cosmic microwave background observations (CMB), baryon acoustic oscillations (BAO), joint light curve analysis (JLA) from supernovae type Ia, redshift space distortions (RSD), and the cosmic chronometers (CC). From the qualitative evolution of the models, we find all of them are able to execute a fine transition from the past decelerating phase to the presently accelerating expansion where in addition, the equation of state of the scalar field (also the effective equation of state) might be close to that of the ΛCDM cosmology depending on its free parameters. From the observational analyses, we find that the scalar field parameters are unconstrained irrespective of all the observational datasets. In fact, we find that the quintessence scalar field models are pretty much determined by the CMB observations since any of the external datasets such as BAO, JLA, RSD, CC does not add any constraining power to CMB. Additionally, we observe a strong negative correlation between the parameters H0 (present value of the Hubble parameter), Ωm0 (density parameter for the matter sector, i.e., cold dark matter plus baryons) exists, while no correlation between H0, and σ8 (amplitude of the matter fluctuation) are not correlated. We also comment that the present models are unable to reconcile the tension on H0. Finally, we conclude our work with the Bayesian analyses which report that the non-interacting ΛCDM model is preferred over all the quintessence scalar field models.

show abstract

“…Thawing models are much sensitive to initial conditions. Some of the models of this class have been studied in [57,58]. The thawing, tracker and scaling models have been discussed in [59].…”

Section: Evolution Equations and Attractorsmentioning

confidence: 99%

Observational constraints on the generalized α attractor model

Shahalam

Myrzakulov

Myrzakul

et al. 2018

Int. J. Mod. Phys. D

Self Cite

View full text Add to dashboard Cite

We study the generalized α attractor model in the context of the late time cosmic acceleration. The model interpolates between the scaling freezing and thawing dark energy models. In the slow roll region, the original potential is modified whereas the modification ceases in the asymptotic region and the effective potential behaves as the quadratic one. In our setting, the field rolls slowly around the present epoch and mimics the scaling behavior in the future. We obtain observational constraints on the model parameters by using an integrated data base (SN+Hubble+BAO+CMB).

show abstract

Om diagnostic applied to scalar field models and slowing down of cosmic acceleration

Cited by 60 publications

References 75 publications

Cosmic acceleration from coupling of baryonic and dark matter components: Analysis and diagnostics

Cosmic acceleration from coupling of baryonic and dark matter components: Analysis and diagnostics

Constraints on quintessence scalar field models using cosmological observations

Observational constraints on the generalized α attractor model

Contact Info

Product

Resources

About