Magnetized String Cosmology in Anisotropic Bianchi-II Space-time with Variable Cosmological Term-Λ

Jotania, Kanti; Yadav, Padminin; Faruqi, Shahab

doi:10.1007/s10773-010-0652-3

Cited by 9 publications

(4 citation statements)

References 91 publications

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“…The reason for this is the physics. The cosmological models have been explored by Yadav (2009), Saha & Boyadjiev (2004), Pedram et al (2008), Biswas & Mazumdar (2009) and Jotania et al (2011) in which the cosmological constant is negative. At present, estimation of Λ is not simply trapped in any case; it is also uncertain and circumlocutory.…”

Section: Case 2: Model Based On Sn Ia Union Datamentioning

confidence: 99%

Stability of LRS Bianchi type-I cosmological models in f(R, T)-gravity

Sharma

Zia

Pradhan

et al. 2019

Res. Astron. Astrophys.

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This paper examines the stability of the transition from the early decelerating stage of the Universe to the recent accelerating stage for the perfect fluid cosmological {locally rotationally symmetric (LRS) Bianchi-I model in f(R, T) theory. To determine the solution of field equations, the idea of a time-varying deceleration parameter (DP) which yields a scale factor, for which the Universe attains a phase transition scenario and is consistent with recent cosmological observations, is used. The time-dependent DP yields a scale factor , where β and k are respectively arbitrary and integration constants. By using the recent constraints (H0 = 73.8, and q0 = −0.54) from Type Ia Supernova (SN Ia) data in combination with Baryonic Acoustic Oscillations (BAO) and Cosmic Microwave Background (CMB) observations (Giostri et al.), we obtain the values of β = 0.0062 and k = 0.000016 for which we have derived a cosmological model from the early decelerated phase to the present accelerating phase. By applying other recent constraints (H0 = 73.8, q0 = −0.73) from SNe Ia Union data (Cunha), we obtain the values of β = 0.0036 and k = 0.000084 for which we have derived a cosmological model in the accelerating phase only. We have compared both models with experimental data. The stability of the background solution has been examined also for the metric perturbations alongside the properties of future singularities in a Universe ruled by dark energy with phantom type fluid. We demonstrate the presence of a stable fixed point with a condition of state ω < − 1 and numerically affirm this is really a late-time attractor in the ghost overwhelmed Universe. Some physical and geometric properties of the model are found and examined.

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Section: Case 2: Model Based On Sn Ia Union Datamentioning

confidence: 99%

Stability of LRS Bianchi type-I cosmological models in f(R, T)-gravity

Sharma

Zia

Pradhan

et al. 2019

Res. Astron. Astrophys.

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“…Models with negative cosmological constant have been investigated by Yadav [62], Saha and Boyadjiev [63], Pedram et al [64], Biswas and Mazumdar [65], Jotania et al . [66]. Really at present the estimation of Λ is not only complicated but it is uncertain and indirect too.…”

Section: Model Ii: When N =mentioning

confidence: 99%

A class of new LRS Bianchi type-I perfect fluid universes with decaying vacuum energy density Λ

Pradhan

Jotania

2011

Indian J Phys

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A class of new LRS Bianchi type-I cosmological models with a variable cosmological term is investigated in presence of perfect fluid. A procedure to generate new exact solutions to Einstein's field equations is applied to LRS Bianchi type-I space-time. Starting from some known solutions a class of new perfect fluid solutions of LRS Bianchi type-I are obtained. The cosmological constant L is found to be positive and a decreasing function of time which is supported by results from recent supernovae Ia observations. The physical and geometric properties of spatially homogeneous and anisotropic cosmological models are discussed.

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“…Throne [39] has explained this assumptive condition. In the literature, many authors like Pradhan [40], Jotania et al [41], Akarsu [42] have assumed this condition for the development of physically viable cosmological models.…”

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confidence: 99%

Model for Modified Holographic Ricci Dark Energy in Gravitation Theory of Branc Dicke

Dixit

Singhal

Zeyauddin

2021

Walailak J Sci & Tech

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In this cosmological model, we have studied the spatially homogeneous and anisotropic Bianchi type and axially symmetric model filled with dark matter and dark energy in Brans-Dicke’s [1] theory of gravitation. Here, we consider the modified holographic Ricci dark energy defined by Chen and Jing [21] as the suitable condition of dark energy. To obtain a solution we assumed the scale factor used Mishra et al. [43]. We have solved field equations of Brans-Dicke theory of gravitation with the help of an axially symmetric anisotropic Bianchi-type space-time. We have determined the cosmological parameters, namely, EoS parameter, MHRDE density, matter density, skewness parameter, and BD scalar field. Here the various phenomena like the expanding universe, and shift from anisotropy to isotropy are observed in this model. A detailed physical discussion of these dynamical parameters are presented graphically. Some physical and geometrical behaviours of the models are also discussed and found to be in good agreement with the recent observations (OHD+JLA) datasets.

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Magnetized String Cosmology in Anisotropic Bianchi-II Space-time with Variable Cosmological Term-Λ

Cited by 9 publications

References 91 publications

Stability of LRS Bianchi type-I cosmological models in f(R, T)-gravity

Stability of LRS Bianchi type-I cosmological models in f(R, T)-gravity

A class of new LRS Bianchi type-I perfect fluid universes with decaying vacuum energy density Λ

Model for Modified Holographic Ricci Dark Energy in Gravitation Theory of Branc Dicke

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