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Behrang Mostaghel

Publications and source records attributed to Behrang Mostaghel.

2 recordsLinked to original sources

Interacting Dark Side of Universe Through Generalized Uncertainty Principle

We investigate the impact of the generalized uncertainty principle proposed by some approaches to quantum gravity such as string theory and doubly special relativity on the cosmology. Using generalized Poisson brackets, we obtain the modified Friedmann and Raychaudhuri equations and suggest a dynamical dark energy to explain the late time acceleration of the Universe. After considering the interaction between dark matter and dark energy, originated from the minimal length, we obtain the effective cosmological parameters and equation of state parameter for dark matter and dark energy. Finally, we show that the resulting model is equivalent to the Phantom and Tachyon fields.

gr-qc

Non-minimal Derivative Coupling Scalar Field and Bulk Viscous Dark Energy

Inspired by thermodynamical dissipative phenomena, we consider bulk viscosity for dark fluid in a spatially flat two-component Universe. Our viscous dark energy model represents Phantom crossing avoiding Big-Rip singularity. We propose a non-minimal derivative coupling scalar field with zero potential leading to accelerated expansion of Universe in the framework of bulk viscous dark energy model. In this approach, coupling constant ($κ$) is related to viscosity coefficient ($γ$) and energy density of dark energy at the present time ($Ω_{\rm DE}^0$). This coupling is bounded as $κ\in [-1/9H_0^2(1-Ω_{\rm DE}^0), 0]$ and for $γ=0$ leads to $κ=0$. To perform robust analysis, we implement recent observational data sets including Joint Light-curve Analysis (JLA) for SNIa, Gamma Ray Bursts (GRBs) for most luminous astrophysical objects at high redshifts, Baryon Acoustic Oscillations (BAO) from different surveys, Hubble parameter from HST project, {\it Planck} data for CMB power spectrum and CMB Lensing. Joint analysis of JLA$+$GRBs$+$BAO$+$HST shows that $Ω_{\rm DE}^0=0.696\pm 0.010$, $γ=0.1404\pm0.0014$ and $H_0=68.1\pm1.3$ at $1σ$ confidence interval. {\it Planck} TT observation provides $γ=0.32^{+0.31}_{-0.26}$ at $68\%$ confidence limit for viscosity coefficient. Tension in Hubble parameter is alleviated in this model. Cosmographic distance ratio indicates that current observed data prefer to increase bulk viscosity. Finally, the competition between Phantom and Quintessence behavior of viscous dark energy model can accommodate cosmological old objects reported as a sign of age crisis in $Λ$CDM model.

astro-ph.CO