In this work the modified Chaplygin gas is related to a cosmological scalar field. Analytical results, more general than the solutions previously shown in the literature, are presented for the case when the curvature is absent, and one entirely new particular result is shown for a case where there is curvature. Also, it is emphasized here that one interesting feature of the scalar field associated to the modified Chaplygin gas is the possible presence of two minima in its potential. Finally, it is argued that the scalar field representation of the Chaplygin gas can be another useful tool in the study of the evolution of perturbations and, as an example of this, a new analytical result for the density contrast is presented.
In this work, we have considered the Friedmann-Robertson-Walker (FRW) model of the universe where bounce occurs and the universe is filled with Generalized Cosmic Chaplygin Gas (GCCG) or Variable Modified Chaplygin Gas (VMCG). We have studied the stability analysis through dynamical system for both models and found the critical points in flat, open and closed universe. In presence of scalar field, the dynamical behavior of scale factor and Hubble parameter is described in both models. Finally, we have analyzed the energy conditions for both the models in bouncing universe.
Modified Chaplygin Gas has been successful in describing the cosmic history of the universe from radiation to $Λ$CDM in standard cosmology, while particle creation mechanism in nonlinear thermodynamics can be used to explain inflation as well as late time acceleration. The present work is an attempt to explore the possibilities of obtaining an alternative explanations to cosmic evolution when modified Chaplygin gas is used in the context of particle creation mechanism.
We consider a universe filled by a modified generalized Chaplygin gas together with a pressureless dark matter component. We get a thermodynamical interpretation for the modified generalized Chaplygin gas confined to the apparent horizon of FRW universe, whiles dark sectors do not interact with each other. Thereinafter, by taking into account a mutual interaction between the dark sectors of the cosmos, we find a thermodynamical interpretation for interacting modified generalized Chaplygin gas. Additionally, probable relation between the thermal fluctuations of the system and the assumed mutual…
We assume that the negative cosmological constant as a thermodynamical pressure and the asymptotically anti-de Sitter (AdS) black hole thermodynamics with modified Chaplygin gas. We have written the mass of the black hole, volume, entropy and temperature due to the thermodynamic system. We find a new solution of Einstein's field equations of AdS black hole with modified Chaplygin gas as a thermodynamic system. We also examine the weak, strong and dominant energy conditions for the source fluid of black hole. We also show that the thermodynamic black hole with Chaplygin gas can be considered as…
The modified Chaplygin gas (MCG) cosmological model is derived by using the geometrothermodynamics (GTD) formalism. We show that the MCG corresponds to a system with internal thermodynamic interaction and describes the current accelerated expansion of the universe. Moreover, we also show that the MCG can be interpreted as a unified model for dark energy and dark matter that is perfectly consistent with the current SNe observations and CMB anisotropy measurements.
In this paper, we study the existence of strange star in the background of f (T) modified gravity where T is a scalar torsion. In KB metric space, we derive the equations of motion using anisotropic property within the spherically strange star with modified chaplygin gas in the framework of modified f (T) gravity. Then we obtain many physical quantities to describe the physical status such as anisotropic behavior, energy conditions and stability. By the matching condition, we calculate the unknown parameters to evaluate the numerical values of mass, surface redshift etc. from our model to make…
The estimation of parameters of generalized cosmic Chaplygin gas and viscous modified Chaplygin gas and Accretions around Black Hole in the background of Einstein-Aether gravity
In this paper, we examine the thermodynamic features of an exotic fluid known as modified cosmic Chaplygin gas in the context of homogeneous isotropic universe model. For this purpose, the behavior of physical parameters are discussed that help to analyze nature of the universe. Using specific heat formalism, the validity of third law of thermodynamics is checked. Furthermore, with the help of thermodynamic entities, the thermal equation of state is also discussed. The thermodynamic stability is explored by means of adiabatic, specific heat and isothermal conditions from classical thermodynami…
We present a reconstruction technique for models of $f(R)$ gravity from the Chaplygin scalar field in flat de Sitter spacetimes. Exploiting the equivalence between $f(R)$ gravity and scalar-tensor theories, and treating the Chaplygin gas as a scalar field model in a universe without conventional matter forms, the Lagrangian densities for the $f(R)$ action are derived. Exact $f(R)$ models and corresponding scalar field potentials are obtained for asymptotically de Sitter spacetimes in early and late cosmological expansion histories. It is shown that the reconstructed $f(R)$ models all have Gene…
In this paper, the model of interaction is studied between $f(T,\mathcal{T})$ gravity and modified Chaplygin gas in FRW-flat metric. We obtain the Friedmann equations in the framework of teleparallel gravity by vierbein field. We consider that Universe dominates by components of cold matter, dark energy and modified Chaplygin gas. In what follows we separately write the corresponding continuity equations for components of Universe. Also, dark energy EoS and effective EoS are obtained with respect to redshift, thereafter the corresponding cosmological parameters are plotted in terms of redshift…
This paper explores the possibility of treating the exotic Chaplygin-gas (CG) fluid model as some manifestation of an $f(T)$ gravitation. To this end, we use the different cosmological CG equations of state, compare them with the equation of state for the modified teleparallel gravity and reconstruct the corresponding Lagrangian densities. We then explicitly derive the equation of state parameter of the torsion fluid $w_T$ and study its evolution for vacuum-torsion, radiation-torsion, dust-torsion, stiff fluid torsion, and radiation-dust-torsion multi-fluid systems. The obtained Lagrangians ha…
We want to study the perturbation growth of an initial seed of an ellipsoidal shape in Top-Hat collapse model of structure formation in the Modified Chaplygin gas cosmology. Considering reasonable values of the constants and the parameters of the model under study, it is shown that a very small deviation from spherical symmetry (ellipsoidal geometry) in the initial seed leads to a final highly non-spherical structure which can be considered as a candidate for justifying already known cosmological structures as cosmic walls and filaments.
We have considered flat Friedmann-Robertson-Walker (FRW) model of the universe and reviewed the modified Chaplygin gas as the fluid source. Associated with the scalar field model, we have determined the Hubble parameter as a generating function in terms of the scalar field. Instead of hyperbolic function, we have taken Jacobi elliptic function and Abel function in the generating function and obtained modified Chaplygin-Jacobi gas (MCJG) and modified Chaplygin-Abel gas (MCAG) equation of states, respectively. Next, we have assumed that the universe filled in dark matter, radiation, and dark ene…
In this paper we found a new model for compact star with anisotropic matter distribution considering the new version of Chaplygin fluid equation of state of Errehymy and Daoud (2021). We specify the particular form of the metric potential proposed for Thirukanesh and Ragel (2012) and generalized for Malaver (2014) in order to integrate the Einstein`s field equations. The obtained model satisfies all physical properties expected in a realistic star. The radial pressure, energy density, metric coefficients, anisotropy and mass are well defined and are regular in the stellar interior. The results…
In this paper, we examine the possible realization of a new family of inflation called "shaft inflation" by assuming the modified Chaplygin gas model and tachyon scalar field. We also consider the special form of dissipative coefficient as $Γ={a_0}\frac{T^{3}}{ϕ^{2 }}$ and calculate the various inflationary parameters in the scenario of strong and weak dissipative regimes. In order to examine the behavior of inflationary parameters, the planes of $n_s - ϕ,~n_s - r$ and $n_s - α_s$ (where $n_s,~α_s,~r$ and $ϕ$ represent spectral index, its running, tensor to scalar ratio and scalar field respec…
In this work, we establish a correspondence between the interacting holographic, new agegraphic dark energy and generalized Chaplygin gas model in Bianchi type I universe. In continue, we reconstruct the potential of the scalar field which describes the generalized Chaplygin cosmology. Cosmological solutions are obtained when the kinetic energy of the phantom field is order of the anisotropy and dominates over the potential energy of the field. We investigate observational constraints on the generalized Chaplygin gas, holographic and new agegraphic dark energy models as the unification of dark…
In this paper we consider the flat FRW cosmology with a scalar field coupled with the metric along with generalized Chaplygin gas and perfect fluid comprising the matter sector. We use the Schutz's formalism to deal with the generalized Chaplygin gas sector. The full theory is then quantized canonically using the Wheeler-DeWitt Hamiltonian formalism. We then solve the WD equation with appropriate boundary conditions. Then by defining a proper completeness relation for the self-adjointness of the WD equation we arrive at the wave packet for the universe. It is observed that the peak in the prob…
In this paper, we have studied flat Friedmann--Lema\^ıtre--Robertson--Walker (FLRW) model with modified Chaplygin gas (MCG) having equation of state $p_{m}=Aρ-% \frac{B}{ρ^{γ}}$, where $0\leq A\leq 1$, $0\leq γ\leq 1$ and $B$ is any positive constant in }${\footnotesize f(R,T)}${\footnotesize \ gravity with particle creation. We have considered a simple parametrization of the Hubble parameter $H$ in order to solve the field equations and discussed the time evolution of different cosmological parameters for some obtained models showing unique behavior of scale factor. We have also discussed the…
