Decoupling of the general scalar field mode and the solution space for Bianchi type I and V cosmologies coupled to perfect fluid sources

Christodoulakis, T.; Grammenos, Th.; Helias, C.; Kevrekidis, P. G.; Spanou, A.

doi:10.1063/1.2188210

Cited by 38 publications

(35 citation statements)

References 59 publications

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“…A number of authors such as Farnswerth (1967), Collins (1974), Maartens and Nel (1978), Wainwright et al (1979), Beesham (1986), Maharaj and Beesham (1988), Shri Ram (1990), Camci et al (2001), Meena and Bali (2004) and Pradhan and Rai (2004), have studied Bianchi type-V models in different physical contexts. Christodoulakis et al (2000Christodoulakis et al ( , 2006 have studied untilted diffuse matter Bianchi V universes with perfect fluid and scalar field coupled to perfect fluid sources obeying a general eqation of state. Following the work of Saha (2006), Chaubey (2006, 2007) have presented the quadrature form of metric functions for Bianchi type-V model with perfect fluid and viscous fluid.…”

Section: Introductionmentioning

confidence: 99%

Bianchi type-V perfect fluid space-time models in general relativity

Singh

Ram²,

Zeyauddin³

2008

Astrophys Space Sci

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The law of variation for the generalized mean Hubble's parameter in the case of a spatially homogeneous and anisotropic Bianchi type-V space-time metric that yields a constant value of deceleration parameter, is presented. The variation for Hubble's parameter generates two types of solutions for the average scale factor one is of power-law type and second is of the exponential form. Using these two forms, Einstein's field equations for perfect fluid Bianchi type-V models are solved separately that correspond to singular and non-singular models respectively. We find that the constant value of deceleration parameter is reasonable for description of the present day universe. We also find that the universe decelerates for positive value of deceleration parameter where as it accelerates for negative one. The behaviors of observationally important parameters such as expansion scalar, mean anisotropic parameter and shear scalar are discussed. Exact expressions for look-back time, luminosity distance and event horizon versus redshift are derived and their significances are discussed in detail. It has been observed that the solutions are compatible with the results of recent observations.

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Section: Introductionmentioning

confidence: 99%

Bianchi type-V perfect fluid space-time models in general relativity

Singh

Ram²,

Zeyauddin³

2008

Astrophys Space Sci

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“…(32), a nontrivial complication is that the time dependent coefficient Γ depends on the reparametrization of time through Ω. Nevertheless, the original equation (29) has been solved in [31]. This may, in turn, provide valuable insights in the solution of such time-dependent EP equations; this would be an interesting direction for future studies in such time-dependent EP settings.…”

Section: Anisotropic Scalar Field Cosmologiesmentioning

confidence: 99%

From Feshbach-resonance managed Bose–Einstein condensates to anisotropic universes: Applications of the Ermakov–Pinney equation with time-dependent nonlinearity

et al. 2008

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In this work we revisit the topic of two-dimensional Bose-Einstein condensates under the influence of time-dependent magnetic confinement and time-dependent scattering length. A moment approach reduces the examination of moments of the wavefunction (in particular, of its width) to an ErmakovPinney (EP) ordinary differential equation (ODE). We use the well-known structure of the solutions of this nonlinear ODE to "engineer" trapping and interatomic interaction conditions that lead to condensates dispersing, breathing or even collapsing. The advantage of the approach is that it is fully tractable analytically, in excellent agreement with our numerical observations. As an aside, we also discuss how similar time-dependent EP equations may arise in the description of anisotropic scalar field cosmologies.

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“…Bianchi type V cosmological models have been studied by several researchers such as Farnsworth [2], Collins [3] Maartens and Nel [4], Wainwright et al [5], Beesham [6], Maharaj and Beesham [7], Hewitt and Wainwright [8], Camci et al [9], Meena and Bali [10], Pradhan et al [11,12], Aydogdu and Salti [13] in different physical contexts. Christodoulakis et al [14][15][16] have studied un-tilted diffuse matter Bianchi V universe with perfect fluid and scalar field coupled to perfect fluid sources obeying a general equation of state. Following the work of Saha [17], Singh and Chaubey [18,19] have obtained the quadrature form of metric function for Bianchi type-V model with perfect fluid and viscous fluid.…”

mentioning

confidence: 99%

Some Exact Bianchi Type-V Perfect Fluid Cosmological Models with Heat Flow and Decaying Vacuum Energy Density Λ: Expressions for Some Observable Quantities

Pradhan¹,

Jotania

2010

Int J Theor Phys

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In this paper we have obtained some new exact solutions of Einstein's field equations in a spatially homogeneous and anisotropic Bianchi type-V space-time with perfect fluid distribution along with heat-conduction and decaying vacuum energy density by applying the variation law for generalized Hubble's parameter that yields a constant value of deceleration parameter. We find that the constant value of deceleration parameter is reasonable for the present day universe. The variation law for Hubble's parameter generates two types of solutions for the average scale factor, one is of power-law type and other is of the exponential form. Using these two forms, Einstein's field equations are solved separately that correspond to expanding singular and non-singular models of the universe respectively. The cosmological constant is found to be a decreasing function of time and positive which is corroborated by results from recent supernovae Ia observations. Expressions for lookback time-redshift, neoclassical tests (proper distance d(z)), luminosity distance red-shift and event horizon are derived and their significance are described in detail. The physical and geometric properties of spatially homogeneous and anisotropic cosmological models are discussed.

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Decoupling of the general scalar field mode and the solution space for Bianchi type I and V cosmologies coupled to perfect fluid sources

Cited by 38 publications

References 59 publications

Bianchi type-V perfect fluid space-time models in general relativity

Bianchi type-V perfect fluid space-time models in general relativity

From Feshbach-resonance managed Bose–Einstein condensates to anisotropic universes: Applications of the Ermakov–Pinney equation with time-dependent nonlinearity

Some Exact Bianchi Type-V Perfect Fluid Cosmological Models with Heat Flow and Decaying Vacuum Energy Density Λ: Expressions for Some Observable Quantities

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