A class of dynamical dark energy models, dubbed Spinor Quintom, can be constructed by a spinor field ψ with a nontraditional potential. We find that, if choosing suitable potential, this model is able to allow the equation-of-state to cross the cosmological constant boundary without introducing any ghost fields. In a further investigation, we show that this model is able to mimic a perfect flui...

In this paper, we continue our previous work of studying viscous generalized Chaplygin gas as a unified dark fluid but the bulk viscosity perturbations. By using the currently available cosmic observational data from SNLS3, BAO, HST, and recently released Planck, we obtain a constraint on the bulk viscosity coefficient: ζ0 = 0.0000138+0.00000614+0.0000145+0.0000212 −0.0000105−0.0000138−0.000013...

We investigate exact solution in higher dimensional Husain model for a null fluid source with pressure p and density ρ are related by the following relations (i) p = kρ, (ii) p = kρ− B(v) ρα (variable modified Chaplygin) and (iii) p = kρ (polytropic). We have studied the nature of singularity in gravitational collapse for the above equations of state and also for different choices of the of the...

A cosmological model with an exotic fluid is investigated. We show that the equation of state of this “modified Chaplygin” gas can describe the current accelerated expansion of the universe. We then reexpress it as FRW cosmological model containing a scalar field φ and find its self–interacting potential. Moreover motivated by recent works of Sen [5, 6] and Padmanbhan [13] on tachyon field theo...