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Journal articles on the topic 'Modelos de bianchi'

Author: Grafiati

Published: 4 June 2021

Last updated: 7 February 2022

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1

Chirde, Dr Vilas R., and Vijay P. Kadam. "Bianchi Type Bulk Viscous String Cosmological Models in Modified Theory of Gravity." International Journal of Scientific Research 3, no. 5 (June 1, 2012): 85–90. http://dx.doi.org/10.15373/22778179/may2014/28.

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2

SZYDŁOWSKI, MAREK, and ADAM KRAWIEC. "BIANCHI COSMOLOGIES AS DYNAMICAL SYSTEMS WITHOUT THE CONSTRAINT." International Journal of Modern Physics A 15, no. 17 (July 10, 2000): 2771–91. http://dx.doi.org/10.1142/s0217751x00001269.

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The Bianchi class A cosmology is treated as a nonlinear dynamical system. In the new variables in which Hamiltonian constraint is solved algebraically, the Bianchi class A model assumes the form of autonomous dynamical system in ℝ4 with polynomial form of vector field. It is proposed that the dimension of minimum reduced phase spaces of unconstrained autonomous systems be treated as a measure of generality of solution. The behavior of these models is studied in terms of qualitative analysis of differential equations. It is shown that the more general Bianchi IX and Bianchi VIII models (called Mixmaster models) can be presented as four-dimensional. We argue that the reduced Mixmaster dynamical systems are chaotic in the same sense as the original ones. The Bianchi I and Bianchi II world models are described by one-dimensional and two-dimensional systems, respectively. We also study dynamics of Bianchi VI0 and Bianchi VII0 models as a three-dimensional dynamical system. For two-dimensional dynamical system, the phase portraits are constructed with the Poincaré sphere which allows the analysis of dynamics both in finite domain and at infinity. For the last class of models we find an invariant submanifold on which systems are analyzed in details.

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3

SPINDEL, PHILIPPE. "COSMOLOGICAL MODELS IN THE R2 THEORY OF GRAVITY." International Journal of Modern Physics D 03, no. 01 (March 1994): 273–76. http://dx.doi.org/10.1142/s0218271894000447.

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I summarize some results obtained in the framework of the R2 theory of gravity: the general Bianchi-I solution in arbitrary dimensions and the description of the asymptotic behaviour of generic Bianchi-IX models in 3+1 dimensions.

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4

DI PIETRO, ELISA, and JACQUES DEMARET. "SCALE FACTOR DUALITY IN STRING BIANCHI COSMOLOGIES." International Journal of Modern Physics D 08, no. 03 (June 1999): 349–61. http://dx.doi.org/10.1142/s0218271899000262.

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We apply the scale factor duality transformations introduced in the context of the effective string theory to the anisotropic Bianchi-type models. We find dual models for all the Bianchi-types [except for types VIII and IX] and construct for each of them its explicit form starting from the exact original solution of the field equations. It is emphasized that the dual Bianchi class B models require the loss of the initial homogeneity symmetry of the dilatonic scalar field.

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5

Rezaei-Aghdam, A. "Bianchi bialgebras and WZW models." Surveys in High Energy Physics 17, no. 1-4 (January 2002): 173–81. http://dx.doi.org/10.1080/0142241021000058109.

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6

Belinchón, J. A. "Scalar-Tensor Bianchi VI Models." Journal of Gravity 2013 (June 5, 2013): 1–11. http://dx.doi.org/10.1155/2013/491905.

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We study how may vary the gravitational and the cosmological “constants,” ( and ) in several scalar-tensor theories with Bianchi III, , and symmetries. By working under the hypothesis of self-similarity we find exact solutions for two different theoretical models, which are the Jordan-Brans-Dicke (JBD) with and the usual JBD model with potential (that mimics the behaviour of . We compare both theoretical models, and some physical and geometrical properties of the solutions are also discussed putting special emphasis on the study of the isotropization of the solutions.

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7

Fujiwara, Y., H. Ishihara, and H. Kodama. "Comments on closed Bianchi models." Classical and Quantum Gravity 10, no. 5 (May 1, 1993): 859–67. http://dx.doi.org/10.1088/0264-9381/10/5/006.

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8

Sklavenites, D. "Geodesic Bianchi type cosmological models." General Relativity and Gravitation 24, no. 1 (January 1992): 47–58. http://dx.doi.org/10.1007/bf00756873.

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9

Asano, Masako, Masayuki Tanimoto, and Noriaki Yoshino. "Supersymmetric Bianchi class A models." Physics Letters B 314, no. 3-4 (September 1993): 303–7. http://dx.doi.org/10.1016/0370-2693(93)91240-n.

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10

Panov, V. F., and O. V. Sandakova. "The Bianchi IX cosmological models." Russian Physics Journal 54, no. 3 (August 2011): 354–59. http://dx.doi.org/10.1007/s11182-011-9621-4.

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11

Saha, Bijan. "Nonlinear Spinor Field in Non-Diagonal Bianchi Type Space-Time." EPJ Web of Conferences 173 (2018): 02018. http://dx.doi.org/10.1051/epjconf/201817302018.

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Within the scope of the non-diagonal Bianchi cosmological models we have studied the role of the spinor field in the evolution of the Universe. In the non-diagonal Bianchi models the spinor field distribution along the main axis is anisotropic and does not vanish in the absence of the spinor field nonlinearity. Hence within these models perfect fluid, dark energy etc. cannot be simulated by the spinor field nonlinearity. The equation for volume scale V in the case of non-diagonal Bianchi models contains a term with first derivative of V explicitly and does not allow exact solution by quadratures. Like the diagonal models the non-diagonal Bianchi space-time becomes locally rotationally symmetric even in the presence of a spinor field. It was found that depending on the sign of the coupling constant the model allows either an open Universe that rapidly grows up or a close Universe that ends in a Big Crunch singularity.

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12

CHAKRABORTY, SUBENOY. "ASYMPTOTIC BEHAVIOR OF HOMOGENEOUS COSMOLOGICAL MODELS ON THE BRANE." Modern Physics Letters A 18, no. 17 (June 7, 2003): 1197–203. http://dx.doi.org/10.1142/s0217732303009277.

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In this work, we have studied the late-time behavior of initially expanding homogeneous cosmological models with a positive cosmological term in Randall–Sundrum brane-world type scenarios. The matter fields are confined in the three-brane, onto which the five-dimensional Weyl tensor has a nonvanishing projection. It is found that all Bianchi models (except IX) exponentially evolve toward the de Sitter solution while the Bianchi IX model also isotropizes but with a restriction on the cosmological parameter.

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13

MACÍAS, A., O. OBREGÓN, and J. SOCORRO. "SUPERSYMMETRIC QUANTUM COSMOLOGY." International Journal of Modern Physics A 08, no. 24 (September 30, 1993): 4291–317. http://dx.doi.org/10.1142/s0217751x93001752.

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Supersymmetric minisuperspace quantization is studied for cosmological models without interaction (Bianchi type I) and for models with interaction like Bianchi type IX, the Taub and the FRW (k=+1) model. In particular for the last two cases the profound differences with standard quantum cosmology are emphasized.

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14

Kabak, Ali, and Sezgin Aygün. "Scalar field solutions for anisotropic universe models in various gravitation theories." International Journal of Geometric Methods in Modern Physics 17, no. 02 (January 13, 2020): 2050025. http://dx.doi.org/10.1142/s0219887820500255.

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In this study, we have investigated homogeneous and anisotropic Marder and Bianchi type I universe models filled with normal and phantom scalar field matter distributions with [Formula: see text] in [Formula: see text] gravitation theory (T. Harko et al., Phys. Rev. D 84 (2011) 024020). In this model, [Formula: see text] is the Ricci scalar and [Formula: see text] is the trace of energy–momentum tensor. To obtain exact solutions of modified field equations, we have used anisotropy feature of the universe and different scalar potential models with [Formula: see text] function. Also, we have obtained general relativity (GR) solutions for normal and phantom scalar field matter distributions in Marder and Bianchi type I universes. Additionally, we obtained the same scalar function values by using different scalar field potentials for Marder and Bianchi type I universe models with constant difference in [Formula: see text] gravity and GR theory. From obtained solutions, we get negative cosmological term value for [Formula: see text] constant scalar potential model with Marder and Bianchi type I universes in GR theory. These results agree with the studies of Maeda and Ohta, Aktaş et al. also Biswas and Mazumdar. Finally, we have discussed and compared our results in gravitation theories.

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15

Apostolopoulos, Pantelis S. "Self-similar Bianchi models: II. Class B models." Classical and Quantum Gravity 22, no. 2 (December 30, 2004): 323–38. http://dx.doi.org/10.1088/0264-9381/22/2/006.

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16

Apostolopoulos, Pantelis S. "Self-similar Bianchi models: I. Class A models." Classical and Quantum Gravity 20, no. 15 (July 9, 2003): 3371–84. http://dx.doi.org/10.1088/0264-9381/20/15/307.

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17

CAPOZZIELLO, S., and R. DE RITIS. "COSMIC NO-HAIR THEOREM IN ANISOTROPIC, NONMINIMALLY COUPLED COSMOLOGIES." International Journal of Modern Physics D 05, no. 02 (April 1996): 209–15. http://dx.doi.org/10.1142/s021827189600014x.

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The cosmic no-hair theorem is generalized for homogeneous and anisotropic spacetimes in which a scalar field is nonminimally coupled to the geometry. The result is that the Wald proof also holds here for all Bianchi-type universes except Bianchi type-IX. However, considering the asymptotic behaviour of parameters, it is possible to find a class of models where the conjecture holds for Bianchi-IX too.

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18

Mohanty, G., S. K. Sahu, and P. K. Sahoo. "Mesonic Stiff Fluid Distribution in Bianchi Type Space-Times." Communications in Physics 14, no. 2 (September 7, 2007): 84–89. http://dx.doi.org/10.15625/0868-3166/14/2/10698.

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The distributions of stiff perfect fluid coupled with zero mass scalar field in LRS Bianchi type-I & Bianchi type-V space times are investigated. Some physical and geometrical properties of the models are discussed.

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19

Bergamini, Roberto, Paolo Sedici, and Paolo Verrocchio. "Inflation for Bianchi type IX models." Physical Review D 55, no. 4 (February 15, 1997): 1896–900. http://dx.doi.org/10.1103/physrevd.55.1896.

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20

Banerjee, A., and Tanwi Ghosh. "Dilaton-electromagnetic fields in Bianchi models." Classical and Quantum Gravity 16, no. 12 (November 10, 1999): 3981–86. http://dx.doi.org/10.1088/0264-9381/16/12/315.

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21

Coussaert, O., and M. Henneaux. "Bianchi cosmological models and gauge symmetries." Classical and Quantum Gravity 10, no. 8 (August 1, 1993): 1607–17. http://dx.doi.org/10.1088/0264-9381/10/8/018.

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22

Tkach, V. I., J. J. Rosales, and O. Obregón. "Supersymmetric action for Bianchi type models." Classical and Quantum Gravity 13, no. 9 (September 1, 1996): 2349–56. http://dx.doi.org/10.1088/0264-9381/13/9/002.

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23

Bretón, Nora. "Ernst potentials for vacuum Bianchi models." General Relativity and Gravitation 25, no. 6 (June 1993): 567–78. http://dx.doi.org/10.1007/bf00757068.

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24

Nayak, B. K., and G. B. Bhuyan. "Bianchi type-V perfect fluid models." General Relativity and Gravitation 18, no. 1 (January 1986): 79–91. http://dx.doi.org/10.1007/bf00843752.

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25

Adhav, K. S., M. V. Dawande, and V. B. Raut. "Bianchi Type-III String Cosmological Models." International Journal of Theoretical Physics 48, no. 3 (September 16, 2008): 700–705. http://dx.doi.org/10.1007/s10773-008-9846-3.

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26

Ellis, G. F. R. "The Bianchi models: Then and now." General Relativity and Gravitation 38, no. 6 (May 13, 2006): 1003–15. http://dx.doi.org/10.1007/s10714-006-0283-4.

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27

Abdel-Megied, M., and E. A. Hegazy. "Bianchi type VI cosmological model with electromagnetic field in Lyra geometry." Canadian Journal of Physics 94, no. 10 (October 2016): 992–1000. http://dx.doi.org/10.1139/cjp-2016-0274.

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Bianchi type VI cosmological model in the presence of electromagnetic field with variable magnetic permeability in the framework of Lyra geometry is presented. An exact solution is introduced by considering that the eigenvalue [Formula: see text] of the shear tensor [Formula: see text] is proportional to the scalar expansion Θ of the model, that is, C = (AB)L, where A, B, and C are the coefficients of the metric and L is a constant. Bianchi type V, III, and I cosmological models are given as special cases of Bianchi type VI. Physical and geometrical properties of the models are discussed.

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28

Rao, V. U. M., K. V. S. Sireesha, and M. Vijaya Santhi. "Bianchi Types II, VIII, and IX String Cosmological Models with Bulk Viscosity in a Theory of Gravitation." ISRN Mathematical Physics 2012 (March 22, 2012): 1–15. http://dx.doi.org/10.5402/2012/341612.

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We have obtained and presented spatially homogeneous Bianchi types II, VIII, and IX string cosmological models with bulk viscosity in a theory of gravitation proposed by Sen (1957) based on Lyra (1951) geometry. It is observed that only vacuum cosmological model exists in case of Bianchi type IX universe. Some physical and geometrical properties of the models are also discussed.

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29

Rao, V. U. M., and M. Vijaya Santhi. "Bianchi Types II, VIII, and IX String Cosmological Models in Brans-Dicke Theory of Gravitation." ISRN Mathematical Physics 2012 (November 28, 2012): 1–8. http://dx.doi.org/10.5402/2012/573967.

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Bianchi types II, VIII, and IX string cosmological models are obtained and presented in a scalar-tensor theory of gravitation proposed by Brans and Dicke (1961) for λ+ρ=0. We also established the existence of only Bianchi type IX vacuum cosmological model for λ=ρ, where λ and ρ are tension density and energy density of strings, respectively. Some physical and geometrical features of the models are also discussed.

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30

PAUL, B. C., and A. BEESHAM. "POWER LAW INFLATION AND THE COSMIC NO HAIR THEOREM IN BRANE WORLD." International Journal of Modern Physics D 14, no. 05 (May 2005): 893–900. http://dx.doi.org/10.1142/s0218271805006262.

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The Cosmic no hair theorem is studied in anisotropic Bianchi brane models which admit power law inflation with a scalar field. We note that all Bianchi models except Bianchi type IX transit to an inflationary regime and the anisotropy washes out at a later epoch. It is found that in the brane world, the anisotropic universe approaches the isotropic phase via inflation much faster than that in the general theory of relativity. The modification in the Einstein field equations on the brane is helpful for a quick transition to an isotropic era from the anisotropic brane. We note a case where the curvature term in the field equation initially drives power law inflation on the isotropic brane which is however not permitted without the brane framework.

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31

Maciejewski, Andrzej J., and Marek Szydłowski. "Bianchi Cosmologies as Dynamical Systems." International Astronomical Union Colloquium 172 (1999): 17–24. http://dx.doi.org/10.1017/s0252921100072377.

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AbstractWe discuss specific properties of dynamical systems originating from cosmology and relativity. In particular, we present results of our study of the Bianchi class A cosmological models. We introduce new variables in which the Hamiltonian constraint for all the class A models is solved algebraically. We present results of dimension reduction of the investigated models.

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32

Nilsson, Ulf S., and Claes Uggla. "Stationary Bianchi type II perfect fluid models." Journal of Mathematical Physics 38, no. 5 (May 1997): 2611–15. http://dx.doi.org/10.1063/1.531998.

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33

Bona, Carles, and Pere Palou. "A new approach to Bianchi V models." Journal of Mathematical Physics 30, no. 11 (November 1989): 2611–13. http://dx.doi.org/10.1063/1.528491.

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34

Maciejewski, Andrzej J., and Marek Szydlowski. "On the integrability of Bianchi cosmological models." Journal of Physics A: Mathematical and General 31, no. 8 (February 27, 1998): 2031–43. http://dx.doi.org/10.1088/0305-4470/31/8/014.

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35

Singh, J. K., and Shri Ram. "String cosmological models of Bianchi type-III." Astrophysics and Space Science 246, no. 1 (1997): 65–72. http://dx.doi.org/10.1007/bf00637400.

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36

Pavelkin, V. N. "Cosmological Bianchi type VIII models with rotation." Russian Physics Journal 55, no. 7 (December 2012): 848–51. http://dx.doi.org/10.1007/s11182-012-9889-z.

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37

Sandin, Patrik. "Tilted two-fluid Bianchi type I models." General Relativity and Gravitation 41, no. 11 (April 10, 2009): 2707–24. http://dx.doi.org/10.1007/s10714-009-0799-5.

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38

Panov, V. F. "Rotating cosmological models of Bianchi type VIII." Soviet Physics Journal 32, no. 5 (May 1989): 403–7. http://dx.doi.org/10.1007/bf00895327.

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39

CHAKRABORTY, NARAYAN CHANDRA, and SUBENOY CHAKRABORTY. "FOUR- AND HIGHER-DIMENSIONAL MODELS WITH DILATON–ELECTROMAGNETIC FIELDS." International Journal of Modern Physics D 10, no. 04 (August 2001): 523–28. http://dx.doi.org/10.1142/s0218271801001001.

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The Einstein–Maxwell dilaton field equations are constructed for four-dimensional Bianchi III and five-dimensional FRW models. The general solutions have been obtained and their asymptotic behavior have been studied.

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40

Patel, L. K., and Sharda S. Koppar. "Some Bianchi type VI0 viscous fluid cosmological models." Journal of the Australian Mathematical Society. Series B. Applied Mathematics 33, no. 1 (July 1991): 77–84. http://dx.doi.org/10.1017/s0334270000008638.

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AbstractThe Einstein field equations have been solved for Bianchi type VI0 spacetimes with viscous fluid source. Four cosmological models are derived. They have nonzero expansion and shear. One of them have nonzero constant shear viscosity coefficient.

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41

Taṣer, Dog̃ukan, and Melis Ulu Dog̃ru. "Conformal symmetric Bianchi type-I cosmologies in f(R) gravity." Modern Physics Letters A 33, no. 23 (July 29, 2018): 1850134. http://dx.doi.org/10.1142/s0217732318501341.

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In this study, we investigate the Bianchi type-I cosmologies with string cloud attached to perfect fluid in f(R) gravity. The field equations and their exact solutions for Bianchi type-I cosmologies with string cloud attached to a perfect fluid are found by using the conformal symmetry properties. The obtained solutions under the varied selection of arbitrary constants indicate three cosmological models. Isotropy conditions for obtained cosmological models are investigated for large value of time. Whether or not the string cloud in conformal symmetric Bianchi type-I universe supports the isotropy condition for the large value of time has been investigated. Also, we examine the contracting and decelerating features of the obtained solutions by using Raychaudhuri equation. Finally, geometrical and physical results of the solutions are discussed.

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42

Singh, T., R. Chaubey, and Ashutosh Singh. "k-essence cosmologies in Kantowski–Sachs and Bianchi space–times." Canadian Journal of Physics 93, no. 11 (November 2015): 1319–23. http://dx.doi.org/10.1139/cjp-2015-0001.

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We investigate Kantowski–Sachs, locally rotationally symmetric Bianchi-I and Bianchi-III cosmology with k-essence and found a set of models that dissipate the initial anisotropy. We obtain the conditions leading to a regular bounce of the average geometry. We show that the linear k-field and polynomial kinetic function models evolve asymptotically to Friedmann–Robertson–Walker cosmologies. For linear k-essence we find the general solution in these cosmologies, when the k-field is driven by an inverse scalar potential.

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43

SINGH, C. P., and SURESH KUMAR. "BIANCHI TYPE-II COSMOLOGICAL MODELS WITH CONSTANT DECELERATION PARAMETER." International Journal of Modern Physics D 15, no. 03 (March 2006): 419–38. http://dx.doi.org/10.1142/s0218271806007754.

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A special law of variation for Hubble's parameter in anisotropic space–time models that yields a constant value of the deceleration parameter is presented. Also, a spatially homogeneous and anisotropic but locally rotationally symmetric (LRS) Bianchi type-II cosmological model is studied with a perfect fluid and constant deceleration parameter. Assuming the equation of state p = γρ, where 0≤γ≤1, and using a special law of variation for the Hubble parameter, we are able to construct many new solutions to Einstein's field equations of LRS Bianchi type-II for four different physical models (dust, radiation, Zel'dovich and vacuum). We discuss the solutions with power-law and exponential expansion and examine a particular class of models. A detailed study of kinematic, geometrical and observational properties is carried out.

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44

Yadav, Anil Kumar, and Ahmad T. Ali. "Invariant Bianchi type I models in f(R,T) gravity." International Journal of Geometric Methods in Modern Physics 15, no. 02 (January 24, 2018): 1850026. http://dx.doi.org/10.1142/s0219887818500263.

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In this paper, we search the existence of invariant solutions of Bianchi type I space-time in the context of [Formula: see text] gravity with special case [Formula: see text]. The exact solution of the Einstein’s field equations are derived by using Lie point symmetry analysis method that yield two models of invariant universe for symmetries [Formula: see text] and [Formula: see text]. The model with symmetries [Formula: see text] begins with big bang singularity while the model with symmetries [Formula: see text] does not favor the big bang singularity. Under this specification, we find out at set of singular and nonsingular solution of Bianchi type I model which present several other physically valid features within the framework of [Formula: see text] gravity.

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45

ERIKSEN, E., and Ø. GRØN. "THE DE SITTER UNIVERSE MODELS." International Journal of Modern Physics D 04, no. 01 (February 1995): 115–59. http://dx.doi.org/10.1142/s0218271895000090.

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The kinematical properties of the de Sitter space-time are reviewed and investigated. The properties of the static sections are clarified. A deduction of the analytic extension, analogous to that of Kruskal and Szekeres for the Schwarzschild space-time, of the static section to the region outside the horizon is given. The representation of the de Sitter space-time as a four-dimensional hyperboloid in Minkowskian five-dimensional spacetime is reviewed. Coordinate transformations between different sections of the de Sitter space-time are found. By means of the transformation formulae the different sections are mapped onto each other in space-time diagrams. These mappings are interpreted kinematically. We have aimed at providing, whenever possible, an intuitive understanding of the kinematical properties of the different sections, and how they are interrelated. Among others we present real coordinate transformations between the static and the three Robertson-Walker sections of the de Sitter space-time on one hand and the vacuum dominated Bianchi type-III model on the other hand. These transformations are used to map the path of a typical Bianchi type-III reference particle into the static and the Robertson-Walker sections.

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46

Capozziello, Salvatore, Vittorio De Falco, and Richard Pincak. "Torsion in Bianchi IX cosmology." International Journal of Geometric Methods in Modern Physics 14, no. 12 (November 24, 2017): 1750186. http://dx.doi.org/10.1142/s0219887817501869.

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The emergence of early cosmological anisotropies and late accelerated expansion can be achieved considering Bianchi cosmological models equipped with torsion. In this paper, we present a Bianchi IX cosmology with torsion where both the previous issues are addressed by the exact solutions derived from the model. The standard Friedman–Robertson–Walker universe is recovered as soon as torsion is switched off and metric becomes isotropic.

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47

Chaubey, Raghavendra, and Rakesh Raushan. "Qualitative study of Bianchi type-I, III and Kantowski–Sachs cosmological models with scalar field." International Journal of Geometric Methods in Modern Physics 13, no. 10 (October 26, 2016): 1650123. http://dx.doi.org/10.1142/s0219887816501231.

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A qualitative analysis of Bianchi type-I, III and Kantowski–Sachs (KS) cosmological models with a scalar field and matter fluid is performed. The analysis of the resulting equations is made by the dynamical system method. To analyze the evolution equations, we have introduced suitable transformation of variables. The evolution of the corresponding solutions is represented by curves in the phase-plane diagram. We analyze the evolution of the effective equation of state parameter for Bianchi type-I, III and KS cosmological models. The nature of critical points are analyzed and stable attractors are examined for each cosmological model.

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48

Chaubey, R., and A. K. Shukla. "Holographic dark energy model with quintessence in general class of Bianchi cosmological models." Canadian Journal of Physics 93, no. 1 (January 2015): 68–79. http://dx.doi.org/10.1139/cjp-2014-0225.

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In this paper, we study the general class of Bianchi cosmological models with holographic dark energy component. We have discussed three types of solutions of the average scale factor for the general class of Bianchi cosmological models by using a special law for the deceleration parameter, which is linear in time with a negative slope. The exact solutions to the corresponding field equations are also obtained. All the physical parameters are calculated and discussed in each physically viable cosmological model. For large time (i.e., t → ∞) the models tend asymptotically to an isotropic Friedmann–Robertson–Walker cosmological model. Quintessence scalar field and quintessence potential are also obtained for three different scenarios of scale factor.

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49

KUMAR, SURESH, and ANIL KUMAR YADAV. "SOME BIANCHI TYPE-V MODELS OF ACCELERATING UNIVERSE WITH DARK ENERGY." Modern Physics Letters A 26, no. 09 (March 21, 2011): 647–59. http://dx.doi.org/10.1142/s0217732311035018.

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The paper deals with a spatially homogeneous and anisotropic universe filled with perfect fluid and dark energy components. The two sources are assumed to interact minimally together with a special law of variation for the average Hubble's parameter in order to solve the Einstein's field equations. The law yields two explicit forms of the scale factor governing the Bianchi-V spacetime and constant values of deceleration parameter. The role of dark energy with variable equation of state parameter has been studied in detail in the evolution of Bianchi-V universe. It has been found that dark energy dominates the universe at the present epoch, which is consistent with the observations. The universe achieves flatness after the dominance of dark energy. The physical behavior of the universe has been discussed in detail.

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SINGH, J. K., and N. K. SHARMA. "SOME BIANCHI TYPE-II COSMOLOGICAL MODELS IN LYRA GEOMETRY." International Journal of Modern Physics A 25, no. 12 (May 10, 2010): 2525–33. http://dx.doi.org/10.1142/s0217751x10048330.

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Abstract:

In this work, we have studied the Bianchi type-II anisotropic cosmological models in the theory based on Lyra's geometry in normal gauge in the presence and absence of the magnetic field. The physical and kinematical behaviors of the models have also been discussed.

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