相关论文: Friedmann-Robertson-Walker models do not require z…

In recent years, some studies have drawn attention to the lack of large-angle correlations in the observed cosmic microwave background (CMB) temperature anisotropies with respect to that predicted within the standard $\Lambda$CDM model.…

We study the $f(R)$ theory of gravity using metric approach. In particular we investigate the recently proposed model by Hu-Sawicki, Appleby $-$ Battye and Starobinsky. In this model, the cosmological constant is zero in flat space time.…

New systematic classification of cosmological models of the present Universe is introduced. After making the comparison of these models with all existing observational data three viable models remain: the cold dark matter model with the…

A special model of a massless vector-field is presented, which has an extra modified-gravity-type interaction term in the action. The cosmology of the model is studied with standard noninteracting relativistic matter added. It is found that…

We study the dynamics of the closed scalar field FRW cosmological models in the framework of the so called Unified Dark Matter (UDM) scenario. Performing a theoretical as well as a numerical analysis we find that there is a strong…

Discrepancies between distance measurements and $\Lambda$CDM predictions reveal notable features in the distance-redshift relation, possibly suggesting the presence of an evolving dark energy component. Given the central role of the…

We analyze solutions to Friedmann-Robertson-Walker cosmologies in Brans-Dicke theory, where a scalar field is coupled to gravity. Matter is modelled by a $\gamma$-law perfect fluid, including false-vacuum energy as a special case. Through a…

Nowadays, efforts are being devoted to the study of alternative cosmological scenarios in which modifications of General Relativity have been proposed to explain the late cosmic acceleration without assuming the existence of dark energy. In…

In this work we consider a flat cosmological model with a set of fluids in the framework of supersymmetric cosmology. The obtained supersymmetric algebra allowed us to take quantum solutions. It is shown that only in the case of a…

We consider FLRW cosmological models for perfect fluid (with rho as the energy density) in the frame work of the f(rho) modified theory of gravity [V. N. Tunyak, Russ. Phys. J. 21, 1221 (1978); J. R. Ray, L. L. Smalley, Phys. Rev. D. 26,…

A perfect fluid, spatially flat cosmology in a $f(T)$ model, derived from a recently proposed general Born-Infeld type theory of gravity is studied. Four dimensional cosmological solutions are obtained assuming the equation of state…

Observational constraints guide one forcefully to examine models in which the matter density is substantially less than critical density. Particularly noteworthy are those which are consistent with inflation. For these models, microwave…

Recently there have been claims on model-independent evidence of dynamical dark energy. Herein we consider a fairly general class of cosmological models with a time-evolving cosmological term of the form $\Lambda(H)=C_0+C_H H^2+C_{\dot{H}}…

We provide a detailed analysis of Friedmann-Robertson-Walker universes in a wide range of scalar-tensor theories of gravity. We apply solution-generating methods to three parametrised classes of scalar-tensor theory which lead naturally to…

We complement a recent analysis comparing $R_\mathrm{h}=ct$ with $\Lambda$CDM/$w$CDM using HII galaxies and giant extragalactic HII regions, by carrying out Bayesian model comparison. For this purpose, we calculate the Bayes factors for…

Assuming the validity of the general relativistic description of gravitation on astrophysical and cosmological length scales, we analytically infer that the Friedmann-Robertson-Walker cosmology with Einsteinian cosmological constant, and a…

We present the canonical and quantum cosmological investigation of a four-dimensional, spatially flat, Friedmann-Robertson-Walker (FRW) model that is derived from the bosonic Neveu-Schwarz/Neveu-Schwarz sector of the low-energy M-theory…

A type of exponential correction to General Relativity gives viable modified gravity model of dark energy. The model behaves as $R-2\Lambda$ at large curvature where an effective cosmological constant appears, but it becomes zero in flat…

We investigate a spatially flat Friedmann-Robertson-Walker (FRW) cosmological model with cold dark matter coupled to a dark energy which is given by the modified holographic Ricci cutoff. The interaction used is linear in both dark energy…

We explore a cosmological model composed by a dark matter fluid interacting with a dark energy fluid. The interaction term has the non-linear lambda*(rho_m)^alpha * (rho_e)^beta form, where rho_m and rho_e are the energy densities of the…