arXiv subjects

M R Setare

Publications and source records attributed to M R Setare.

At least 19 recordsLinked to original sources

arXiv2010

Interacting non-minimally coupled canonical, phantom and quintom models of holographic dark energy in non-flat universe

Motivated by our recent work \cite{set1}, we generalize this work to the interacting non-flat case. Therefore in this paper we deal with canonical, phantom and quintom models, with the various fields being non-minimally coupled to gravity, within the framework of interacting holographic dark energy. We employ the holographic model of interacting dark energy to obtain the equation of state for the holographic energy density in non-flat (closed) universe enclosed by the event horizon measured from the sphere of horizon named $L$.

hep-th↗

arXiv2009

Interacting Dark Energy in Hořava-Lifshitz Cosmology

In the usual Hořava-Lifshitz cosmological models, the scalar field is responsible for dark matter. Using an additional scalar field, Saridakis \cite{sari} has formulated Hořava-Lifshitz cosmology with an effective dark energy sector. In the paper \cite{sari} the scalar fields do not interact with each other, here we extend this work to the interacting case, where matter scalar field $ϕ$ interact with dark energy scalar field $σ$. We will show that in contrast with \cite{sari}, where $σ$-filed is absent, we can obtain $w_d ^{\rm eff}<-1$, that is we result to an effective dark energy presenting phantom behaviour. This behaviour is pure effect of the interaction.

hep-th↗

arXiv2009

Vacuum quantum effect for curved boundaries in static Robertson--Walker spacetime

The energy-momentum tensor for a massless conformally coupled scalar field in the region between two curved boundaries in $k=-1$ static Robertson--Walker spacetime is investigated. We assume that the scalar field satisfies the Dirichlet boundary condition on the boundaries. $k=-1$ Robertson--Walker space is conformally related to the Rindler space, as a result we can obtain vacuum expectation values of energy-momentum tensor for conformally invariant field in Robertson--Walker space from the corresponding Rindler counterpart by the conformal transformation.

hep-th↗

arXiv2009

Non-minimal Maxwell-Modified Gauss-Bonnet Cosmologies: Inflation and Dark Energy

In this paper we show that power-law inflation can be realized in non-minimal gravitational coupling of electromagnetic field with a general function of Gauss-Bonnet invariant. Such a non-minimal coupling may appear due to quantum corrections. We also consider modified Maxwell-$F(G)$ gravity in which non-minimal coupling between electromagnetic field and $f(G)$ occur in the framework of modified Gauss-Bonnet gravity. It is shown that inflationary cosmology and late-time accelerated expansion of the universe are possible in such a theory.

hep-th↗

arXiv2009

Cosmic acceleration and crossing of $ω=-1$ in non-minimal modified Gauss-Bonnet gravity

Modified Gauss-Bonnet, i.e, $f(G)$ gravity is a possible explanation of dark energy. Late time cosmology for the $f(G)$ gravity non-minimally coupled with a free massless scalar field have been investigated in Ref. [32]. In this paper we generalize the work of Ref. [32] by including scalar potential in the matter Lagrangian which is non-minimally coupled with modified Gauss-Bonnet gravity. Also we obtain the conditions for having a much more amazing problem than the acceleration of the universe, i.e: crossing of $ω=-1$, in $f(G)$ non-minimally coupled with tachyonic Lagrangian.

hep-th↗

arXiv2009

String Inspired Quintom Model with Non-minimally Coupled Modified Gravity

In this paper we consider a quintom model of dark energy with non-minimal coupling between scalar field and modified gravity which is known $f(R)$ gravity. The Lagrangian for scalar field has been inspired by tachyonic Lagrangian in string theory. Then we obtain the equation of state (EoS), and the condition required for the model parameters when $ω$ crosses over -1. This model shows that for having $ω$ across over -1, one doesn't need to add some higher derivative operator in the tachyonic part of action (the way that usually used to obtain crossing of the phantom divide line for EoS parameter).

hep-th↗

arXiv2009

Interacting tachyon dark energy in non-flat universe

In this paper we study the tachyon cosmology in non-interacting and interacting cases in non-flat FRW universe. Then we reconstruct the potential and the dynamics of the tachyon field which describe tachyon cosmology.

gr-qc↗

arXiv2009

Thermodynamical picture of the interacting holographic dark energy model

In the present paper, we provide a thermodynamical interpretation for the holographic dark energy model in a non-flat universe. For this case, the characteristic length is no more the radius of the event horizon ($R_E$) but the event horizon radius as measured from the sphere of the horizon ($L$). Furthermore, when interaction between the dark components of the holographic dark energy model in the non-flat universe is present its thermodynamical interpretation changes by a stable thermal fluctuation. A relation between the interaction term of the dark components and this thermal fluctuation is obtained.

hep-th↗

arXiv2008

Bouncing universe with the non-minimally coupled quintom matter on the warped DGP Brane

We construct a quintom dark energy model with two non-minimally coupled scalar fields, one quintessence and the other phantom field, confined on the warped DGP brane. We study some important issues such as phantom divide line crossing, existence of the bouncing solutions and the stability of the solutions in this framework. We show that this model accounts for crossing of the phantom divide line and realization of the bouncing solutions. This model allows for stability of the solutions in separate regions of the $ω$-$ω'$ phase-plane.

hep-th↗

arXiv2008

Reconstructing a String-Inspired Non-minimally Coupled Quintom Model

Motivated by the recent work of Zhang and Chen \cite{bin}, we generalize their work to the non-minimally coupled case. We consider a quintom model of dark energy with a single scalar field $T$ given by a Lagrangian which inspired by tachyonic Lagrangian in string theory. We consider non-minimal coupling of tachyon field to the scalar curvature, then we reconstruct this model in the light of three forms of parametrization for dynamical dark energy.

hep-th↗

arXiv2008

Holographic Chaplygin DGP cosmologies

In the present paper, we present an extra dimensions inspired model that is built on the DGP brane-world scenario, then we take the dark energy component on the brane to be a Chaplygin gas. After that we consider a holographic model of Chaplygin gas in the framework of DGP cosmology. We show that the holographic Chaplygin gas can mimic a phantom fluid and cross the phantom divide in a DGP brane-world setup.

hep-th↗

arXiv2008

Semiclassical Corrections to the Cardy-Verlinde Formula of Kerr Black Holes

In this letter, we compute the corrections to the Cardy-Verlinde formula of $4-$dimensional Kerr black hole. These corrections are considered within the context of KKW analysis and arise as a result of the self-gravitational effect. Then we show, one can taking into account the semiclassical corrections of the Cardy-Verlinde entropy formula by just redefining the Virasoro operator $L_0$ and the central charge $c$.

hep-th↗

arXiv2007

Interacting generalized Chaplygin gas model in non-flat universe

We employ the generalized Chaplygin gas of interacting dark energy to obtain the equation of state for the generalized Chaplygin gas energy density in non-flat universe. By choosing a negative value for $B$ we see that $w_{\rm Λ}^{eff}< -1$, that corresponds to a universe dominated by phantom dark energy.

gr-qc↗

arXiv2007

Holographic tachyon model of dark energy

In this paper we consider a correspondence between the holographic dark energy density and tachyon energy density in FRW universe. Then we reconstruct the potential and the dynamics of the tachyon field which describe tachyon cosmology.

hep-th↗

arXiv2007

Interacting Holographic Phantom

In this paper we consider the holographic model of interacting dark energy in non-flat universe. With the choice of $c\leq 0.84$, the interacting holographic dark energy can be described by a phantom scalar field. Then we show this phantomic description of the holographic dark energy with $c\leq 0.84$ and reconstruct the potential of the phantom scalar field.

hep-th↗

arXiv2007

Holographic Chaplygin gas model

In this paper we consider a correspondence between the holographic dark energy density and Chaplygin gas energy density in FRW universe. Then we reconstruct the potential and the dynamics of the scalar field which describe the Chaplygin cosmology.

hep-th↗

arXiv2006

Bulk-Brane Interaction and Holographic Dark Energy

In this paper we consider the bulk-brane interaction to obtain the equation of state for the holographic energy density in non-flat universe enclosed by the event horizon measured from the sphere of horizon named $L$. We assumes that the cold dark matter energy density on the brane is conserved, but the holographic dark energy density on the brane is not conserved due to brane-bulk energy exchange. Our calculation show, taking $Ω_Λ=0.73$ for the present time, the lower bound of $w_{\rm Λ}^{eff}$ is -0.9. This implies that one can not generate phantom-like equation of state from an interacting holographic dark energy model in non-flat universe.

hep-th↗

arXiv2006

The holographic dark energy in non-flat Brans-Dicke cosmology

In this paper we study cosmological application of holographic dark energy density in the Brans-Dicke framework. We employ the holographic model of dark energy to obtain the equation of state for the holographic energy density in non-flat (closed) universe enclosed by the event horizon measured from the sphere of horizon named $L$. Our calculation show, taking $Ω_Λ=0.73$ for the present time, the lower bound of $w_{\rm Λ}$ is -0.9. Therefore it is impossible to have $w_{\rm Λ}$ crossing -1. This implies that one can not generate phantom-like equation of state from a holographic dark energy model in non-flat universe in the Brans-Dicke cosmology framework. In the other hand, we suggest a correspondence between the holographic dark energy scenario in flat universe and the phantom dark energy model in framework of Brans-Dicke theory with potential.

hep-th↗