全部 标题 作者
关键词 摘要

OALib Journal期刊
ISSN: 2333-9721
费用：99美元
投递稿件

查看量下载量

Polytropic Bulk Viscous Cosmological Model with Variable G and Λ

DOI: 10.4236/oalib.1100729, PP. 1-8

Subject Areas: Special Theory of Relativity, String Theory

Keywords: Bianchi Type-I Space Time, Bulk Viscosity, Shear Scalar, Expansion Scalar

Full-Text   Cite this paper   Add to My Lib

Abstract

We consider a Bianchi type-I Polytropic bulk viscous fluid cosmological model with variable G and Λ. To get a deterministic model, it is assumed thatand , , , where is the pressure, ρ is the energy density, η is the coefficient of bulk viscosity, α, k, γ and ηo are constants, H is Hubble constant, where k1 > 0, k2 > 0. The solution obtained lead to inflationary phase and the results obtained match with the observations [31] [32]. The case n = 1 for α = 1 is also discussed, relating the results with the observations.

Cite this paper

Tiwari, R. K. , Sharma, M. and Sharma, S. (2014). Polytropic Bulk Viscous Cosmological Model with Variable G and Λ. Open Access Library Journal, 1, e729. doi: http://dx.doi.org/10.4236/oalib.1100729.

References

[1]  Perlmutter, S., et al. (1997) Measurements of the Cosmological Parameters Ω and Λ from the First Seven Supernovae at z ≥ 0.35. The Astrophysical Journal, 483, 565.
http://dx.doi.org/10.1086/304265
[2]  Perlmutter, S., et al. (1999) Measurements of Ω and Λ from 42 High-Redshift Supernova. The Astrophysical Journal, 517, 565.
http://dx.doi.org/10.1086/307221
[3]  Perlmutter, S., et al. (1998) Discovery of a Supernova Explosion at Half the Age of the Universe. Nature, 391, 51-54.
http://dx.doi.org/10.1038/34124
[4]  Riess, A.G., et al. (1998) Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant. The Astronomical Journal, 116, 1009-1038.
http://dx.doi.org/10.1086/300499
[5]  Riess, A.G., et al. (2004) Type Ia Supernova Discoveries at z > 1 From the Hubble Space Telescope: Evidence for Past Deceleration and Constraints on Dark Energy Evolution. The Astro-physical Journal, 607, 665-678.
http://dx.doi.org/10.1086/383612
[6]  Allen, S.W., et al. (2004) Constraints on Dark Energy from Chandra Observations of the Largest Relaxed Galaxy Clusters. Monthly Notices of the Royal Astronomical So-ciety, 353, 457-467.
http://dx.doi.org/10.1111/j.1365-2966.2004.08080.x
[7]  Peebles, P.J.E. and Ratra, B. (2003) The Cosmological Constant and Dark Energy. Reviews of Modern Physics, 75, 559.
http://dx.doi.org/10.1103/RevModPhys.75.559
[8]  Padmanabhan, T. (2003) Cosmological Constant-The Weight of the Vacuum. Physics Reports, 380, 235-320.
http://dx.doi.org/10.1016/S0370-1573(03)00120-0
[9]  Lima, J.A.S. (2004) Alternative Dark Energy Models: An Overview. Brazilian Journal of Physics, 34, 194.
http://dx.doi.org/10.1590/S0103-97332004000200009
[10]  Padmanabhan, T. (2003) Accelerate Expansion of the Universe Driven by Tachyonic Matter. Physical Review D, 66, Article ID: 021301.
[11]  Zhang, H., Guo, Q. and Cai, R.G. (2006) Friedmann Cosmology on Codimension 2 Brane with Time Dependent Tension. Modern Physics Letters A, 21, 159-167.
[12]  Tiwari, R.K. and Sharma, S. (2011) Non-Existence of Shear in Bianchi Type-III String Bulk Viscous Cosmological Model in General Relativity. Chinese Physics Letters, 28, Article ID: 020401.
[13]  Wang, X.X. (2003) Exact Solutions for String Cosmology. Chinese Physics Letters, 20, 615.
http://dx.doi.org/10.1088/0256-307X/20/5/307
[14]  Wang, X.X. (2004) Locally Rotationally Symmetric Bianchi Type-I String Cosmological Model with Bulk Viscosity. Chinese Physics Letters, 21, 1205.
http://dx.doi.org/10.1088/0256-307X/21/7/006
[15]  Wang, X.X. (2005) Bianchi Type-III String Cosmological Model with Bulk Viscosity in General Relativity. Chinese Physics Letters, 22, 29.
http://dx.doi.org/10.1088/0256-307X/22/1/009
[16]  Wang, X.X. (2006) Bianchi Type-III String Cosmological Model with Bulk Viscosity and Magnetic Field. Chinese Physics Letters, 23, 1702.
http://dx.doi.org/10.1088/0256-307X/23/7/013
[17]  Tiwari, R.K. and Sharma, S. (2011) Bianchi Type-I String Cosmological Model with Bulk Viscosity and Time Dependent Λ Term. Chinese Physics Letters, 28, Article ID: 090401.
http://dx.doi.org/10.1088/0256-307X/28/9/090401
[18]  Zeyauddin, M. and Saha, B. (2013) Bianchi Type-V Bulk Viscous Cosmological Models with Particle Creation in General Relativity.
[19]  Beesham, A., Ghosh, S.G. and Lombard, R.G. (2000) Anisotropic Viscous Cosmology with Variable G and Λ. General Relativity and Gravitation, 32, 471-477.
http://dx.doi.org/10.1023/A:1001924300321
[20]  Tiwari, R.K., Tiwari, D. and Shukla, P. (2011) LRS Bianchi Type-II Cosmological Model with a Decaying Lambda Term. Chinese Physics Letters, 29, Article ID: 010403.
http://dx.doi.org/10.1088/0256-307X/29/1/010403
[21]  Tiwari, R.K. (2010) Bianchi Type-I Cosmological Models with Perfect Fluid in General Relativity. Research in Astro- nomy and Astrophysic, 10, 291-300.
[22]  El-Nabulsi, R.A. (2010) Fractional Action-Like Variational Approach, Perturbed Einstein’s Gravity and New Cosmology. FIZIKA B, 19, 103-112.
[23]  El-Nabulsi, R.A. (2010) A Late-Time Cosmological Model with Slowly Growing Gravitational Coupling Constant and Decaying Vacuum Energy Density. FIZIKA B, 19, 187-192.
[24]  El-Nabulsi, R.A. (2010) Accelerated Expansion of the Higher-Dimensional Spatially Flat Universe. FIZIKA B, 19, 233-238.
[25]  El-Nabulsi, R.A. (2010) High-er-Dimensional Non-Singular Cosmology Dominated by a Varying Cosmological Constant. FIZIKA B, 19, 269-282.
[26]  Chang, Z. and Wang, S. (2013) Inflation and Primordial Power Spectra at Anisotropic Spacetime Inspired by Planck’s Constraints on Isotropy of CMB. European Physical Journal C, 73, 2516.
[27]  Wetterich, C. (2014) Variable Gravity Universe. Physical Review D, 89, Article ID: 024005.
http://dx.doi.org/10.1103/PhysRevD.89.024005
[28]  Liu, H. and Wesson, P.S. (2001) Universe Models with a Variable Cosmological Constant and a Big Bounce. The Astrophysical Journal, 562, 1-6.
http://dx.doi.org/10.1086/323525
[29]  Rendall, A.D. (2002) Cosmological Models and Center Manifold Theory. General Relativity and Gravitation, 34, 1277-1294.
http://dx.doi.org/10.1023/A:1019734703162
[30]  Kumar, S. (2011) String Cosmology in Anisotropic Bianchi-II Spacetime. Modern Physics Letters A, 26, 779-793.
[31]  Yadav, A.K. (2011) Some Anisotropic Dark Energy Models in Bianchi Type-V Space-Time. Astrophysics and Space Science, 335, 565-575.
http://dx.doi.org/10.1007/s10509-011-0745-3
[32]  Tiwari, R.K., Tiwari, S.S. and Pandey, P. (2010) A Cosmological Model with Variable G and Λ Term in General Relativity. FIZIKA B, 19, 193.

Full-Text


comments powered by Disqus

Contact Us

service@oalib.com

QQ:3279437679

WhatsApp +8615387084133

WeChat 1538708413




©2008-2020 OALib, Inc | Public user content licensed CC-BY 4.0 unless otherwise specified. OALib ISSN Online: 2333-9721 OALib ISSN Print: 2333-9705