BIANCHI TYPE-III COSMOLOGICAL MODEL WITH VARIABLE G AND Λ-TERM IN GENERAL RELATIVITY
|
|
- Buddy Greer
- 5 years ago
- Views:
Transcription
1 BIANCHI TYPE-III COSMOLOGICAL MODEL WITH VARIABLE G AND Λ-TERM IN GENERAL RELATIVITY HASSAN AMIRHASHCHI 1, H. ZAINUDDIN 2,a, ANIRUDH PRADHAN 2,3 1 Young Researchers Club, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran h.amirhashchi@mahshahriau.ac.ir 2 Laboratory of Computational Sciences and Mathematical Physics, Institute for Mathematical Research, University Putra Malaysia, Serdang, Selangor D.E., Malaysia a : hisham@putra.upm.edu.my 3 Department of Mathematics, Hindu Post-graduate College, Zamania , Ghazipur, India pradhan@iucaa.ernet.in; pradhan.anirudh@gmail.com Received August 1, 2011 Exact solution of Einstein s field equations with variable gravitational and cosmological constant is obtained in presence of perfect fluid for Bianchi III space-time. To get the deterministic solution of the field equations the expansion θ, in the model, is considered as proportional to the eigen value σ 2 2 of the shear tensor σ j i and also the fluid obeys the barotropic equation of state. The value of cosmological constant Λ for the model is found to be small and positive which is supported by the results from recent supernovae Ia observations. Moreover, it is observed that due to the combined effect of time variable Λ and G the universe evolved with deceleration as well as acceleration. The model shows that G varies with time as suggested earlier by Large Number Hypothesis proposed by Dirac. It has been found that all physical and geometric parameters of the model are in fair agreement of observational results. Some physical and geometric properties of the model are also discussed. Key words: Cosmology, Exact solution, Variable G and Λ, Perfect fluid. PACS: Es, k. 1. INTRODUCTION The Einstein field equation has two parameters, the gravitational constant G and the cosmological constant Λ. The Newtonian constant of gravitation G plays the role of a coupling constant between geometry and matter in the Einstein field equation. In an evolving universe, it appears to look at this constant as a function of time. There are significant observational evidence that the expansion of the Universe is undergoing a late time acceleration 1 15]. This, in other words, amounts to saying that in the context of Einstein s general theory of relativity some sort of dark energy, constant or that varies only slowly with time and space dominates the current composition of cosmos. The origin and nature of such an accelerating field poses a RJP Rom. 57(Nos. Journ. Phys., 3-4), Vol , Nos. 3-4, (2012) P , (c) Bucharest, 2012
2 2 Bianchi type-iii cosmological model with variable G and Λ-term in general relativity 749 completely open question. Recently, Riess et al. 16] have presented an analysis of 156 SNe including a few at z > 1.3 from the Hubble Space Telescope (HST) GOOD ACS Treasury survey. They conclude to the evidence for present acceleration q 0 < 0 (q 0 0.7). Observations 16, 17] of Type Ia Supernovae (SNe) allow us to probe the expansion history of the universe leading to the conclusion that the expansion of the universe is accelerating. Observations strongly favor a small and positive value of the effective cosmological constant at the present epoch. Among many possible alternatives, the simplest and most theoretically appealing possibility for dark energy is the energy density stored on the vacuum state of Λ 8πG all existing fields in the universe, i.e., ρ v =, where Λ is the cosmological constant. However, a constant Λ cannot explain the huge difference between the cosmological constant inferred from observation and the vacuum energy density resulting from quantum field theories. In an attempt to solve this problem, variable Λ was introduced such that Λ was large in the early universe and then decayed with evolution 18]. Cosmological scenarios with a time-varying Λ were proposed by several researchers. A number of models with different decay laws for the variation of cosmological term were investigated during last two decades 19 27]. In recent past, a number of authors have considered cosmological models with time-dependent cosmological constant (see 28 36] and references therein). On the other hand, numerous modifications of general relativity to allow for a variable G based on different arguments have been proposed 37]. First time Dirac 38 41] and Dicke 42] suggested a possible time varying gravitational constant. The Large Number Hypothesis (LNH) proposed by Dirac leads to a cosmology when G varies with time. Variation of G has many interesting consequences in astrophysics. Canuto and Narlikar 43] have shown that G-varying cosmology is consistent with whatsoever cosmological observations available at present. A modification linking the variation of G with that of variable Λ-term has been considered within the framework of general relativity by a number of workers 44 47]. This modification is appealing as it leaves the form of Einstein s equations formally unchanged by allowing a variation of G to be accompanied by a change in Λ. Cosmological models with time-dependent G and Λ in the solutions Λ R 2, Λ t 2, were first obtained by Bertolami 48,49]. Variability of G is also supported by observational results coming from Lunar Lase Ranging 50], spinning rate of pulsars 51 53], distant Type Ia Supernovae observations 54], Helioseismological data 55], and white dwarf G 117-B 15A 56, 57]. Also the discovery of the scenario of accelerating universe 2 5], the investigations within the framework of variable G is also not uncommon in the literature. The cosmological models with variable G and Λ have been recently studied by several authors 58 69]. Recently, Ray et al. 72] obtained dark energy models with time-dependent G. Mukhopadhyay et al. 73] studied higher dimensional dark energy with time variable Λ and G. Arbab 74] investigated bulk viscous dark energy
3 750 Hassan Amirhashchi, H. Zainuddin, Anirudh Pradhan 3 models with variable G and Λ. Pradhan et al. 75] also obtained FRW universe with variable G and Λ-term. Recently, Khadekar and Kamdi 76] have obtained exact solution of the Einstein s field equations in higher dimension with variable G and Λ. Recently, Singh et al. 77] and Bali et al. 78] have investigated Bianchi type- III cosmological models with variable G and Λ in presence of perfect fluid and their both solutions are particular and similar. The aforesaid survey of literature clearly indicates that there has been interest in studying Bianchi types models with variable G and Λ. Motivated by the above observations, we consider anisotropic space-time of Bianchi type-iii model in a general form with variable gravitational and cosmological constant and obtained a general and exact solution of Einstein s field equations which is new and different from other author s solutions. The out line of the paper is as follows: in Section 2, the metric and the field equations are described. Section 3 deals with the solutions of the field equations and their geometric and physical properties. Finally, conclusions are summarized in the last Section THE METRIC AND FIELD EQUATIONS We consider the space-time of general Bianchi III type with the metric ds 2 = dt 2 + A 2 (t)dx 2 + B 2 (t)e 2ax dy 2 + C 2 (t)dz 2, (1) where a is constant. The energy momentum tensor for perfect fluid distribution has the form T j i = (ρ + p)v iv j + pg j i, (2) where v i satisfies condition v i v i = 1. (3) Here p is isotropic pressure, ρ is the proper energy density and v i is the four-velocity. In a co-moving coordinate system, we have v i = (0,0,0,1) (4) The Einstein s field equations with time varying G and Λ read as R j i 1 2 Rgj i = 8πG(t)T j i + Λ(t)gj i, (5) where R j i is the Ricci tensor; R = gij R ij is the Ricci scalar, G is the gravitational constant and Λ is cosmological constant. The field equations (5) with (2) for the metric (1) subsequently lead to the following system of equations: Ä A + B B + AḂ AB a2 = 8πG(t)p + Λ(t), (6) A2
4 4 Bianchi type-iii cosmological model with variable G and Λ-term in general relativity 751 B B + C C + ḂĊ = 8πG(t)p + Λ(t), BC (7) Ä A + C C + AĊ = 8πG(t)p + Λ(t), AC (8) AĊ AC + AḂ AB + ḂĊ BC a2 = 8πG(t)ρ + Λ(t). (9) A2 ( ) A A Ḃ = 0. (10) B Here and in what follows an over dot denotes ordinary differentiation with respect to time, t. Vanishing divergence of the Einstein tensor (R j i 1 2 Rgj i ) ;j = 0, (11) leads to 8πĠ(t)ρ + Λ(t) + 8πG(t) ] A ρ + (ρ + p)( A + Ḃ B + Ċ C ) = 0. (12) We now assume that the law of conservation of energy (T ij ;j = 0) gives ( ) A ρ + (ρ + p) A + Ḃ B + Ċ = 0. (13) C Using (12) the above relation yields Ġ(t) = Λ(t) 8πρ, (14) which implies that G(t) increases or decrease as Λ(t) decreases or increases. The spatial volume for the model (1) is given by V 3 = ABCe ax. (15) We define V = (ABCe ax ) 1 3 as the average scale factor so that the Hubble s parameter is anisotropic models may be defined as H = V ( ) V = 1 A 3 A + Ḃ B + Ċ. (16) C We define the generalized mean Hubble s parameter H as H = 1 3 (H x + H y + H z ), (17)
5 752 Hassan Amirhashchi, H. Zainuddin, Anirudh Pradhan 5 where H x = Ȧ A, H y = Ḃ B and H z = Ċ C directions of x, y and z respectively. are the directional Hubble s parameters in the An important observational quantity is the deceleration parameter q, which is defined as q = V V V 2. (18) The velocity field v i as specified by (4) is irrotational. The scalar expansion θ, components of shear σ ij and the average anisotropy parameter A m are defined by Therefore σ 2 = 1 3 A θ = A + Ḃ B + Ċ C, (19) ] σ 11 = A2 2Ȧ 3 A Ḃ B Ċ, (20) C σ 22 = B2 e 2ax 2Ḃ 3 B A ] A Ċ, (21) C σ 33 = C2 2Ċ 3 C A ] A Ḃ, (22) B σ 44 = 0. (23) A 2 A 2 + Ḃ2 B 2 + Ċ2 C 2 AḂ AB ḂĊ BC Ċ A ]. (24) CA 3 ( ) 2 Hi, (25) A m = 1 3 where H i = H i H(i = 1,2,3). i=1 H 3. SOLUTIONS OF THE FIELD EQUATIONS The field equations (6)-(10) are a system of five equations with seven unknown parameters A, B, C, ρ, p, Λ(t) and G(t). Two additional constraints relating these parameters are required to obtain explicit solutions of the system. We firstly consider that the expansion (θ) in the model is proportional to the eigen value σ2 2 of the shear tensor σ j i. This condition leads to B = l 1 (AC) m 1, (26) where l 1 and m 1 are arbitrary constants. Equations (10) leads to A = mb, (27)
6 6 Bianchi type-iii cosmological model with variable G and Λ-term in general relativity 753 where m is an integrating constant. The equations (7) and (8) reduce to B B Ä A + ḂĊ BC AĊ = 0. (28) AC Using (27) in (28) we obtain ( ) B (1 m) B + ḂĊ = 0. (29) BC As m 0, (29) gives which on integration reduces to where k 1 is an integrating constant. From (26) and (31), we obtain 1 ( ) B B + ḂĊ = 0, (30) BC 1 m where l 2 = l 1 1 m l, l = m 1 1 m 1. Using (32) in (31) we get which on integration gives C = (l + 1) 1 ḂC = k 1, (31) B = l 2 C l, (32) C l Ċ = k 1, (33) ] 1 k1 t + k 2, (34) where k 2 is an integrating constant. Using (34) in (32) and (27) we obtain ] l B = l 2 (l + 1) l k1 t + k 2, (35) and ] l A = ml 2 (l + 1) l k1 t + k 2, (36) respectively. Hence the metric (1) reduces to the form ) l ] 2 ds 2 = dt 2 + ml 2 (l + 1) ( l k1 t + k 2 dx 2 + l 2 (l + 1) l e ax( k1 t + k 2 ) l ] 2 dy 2 + ) 1 ] 2 (l + 1) ( 1 k1 t + k 2 dz 2. (37)
7 754 Hassan Amirhashchi, H. Zainuddin, Anirudh Pradhan 7 Using the suitable transformation the metric (37) reduces to where ml 2 (l + 1) l x = X, l2 (l + 1) l y = Y, (l + 1) 1 z = Z, k 1 t + k 2 = T, (38) ds 2 = β 2 dt 2 + T 2L dx 2 + T 2L e 2a N X dy 2 + T 2L l dz 2, (39) β = k 1, M = (l + 1) 1, N = ml 2 M, L = l l + 1. Now we secondly assume that the fluid obeys barotropic equation of state (40) p = γρ, (41) where γ(0 < γ < 1) is a constant. Using (34)-(36) and (41) in (13), we obtain which by integrating leads to ρ ρ + γ)(1 + 2l) = (1, (42) lβt ρ =, (43) T (1+γ)(1+2l) where k 3 is an integrating constant. The equations (34)-(36), (9) and (14) lead to k 3 8πG = 2a2 L N 2 T L (1+3l)+γ(2l 2 +3) k 3 The equations (43), (44) and (14) also yield l 2 2L2 (l + 2) lβ 2 k 3 T γ(1+2l)+1 l. (44) Λ = 2a2 L 2 (1 + 3l) + γ(2l 2 N 2 + 3l + 1) ] T α l αk 2 L2 (l + 2) 1 3 lβ 2 k 3 T 2, (45) where α = (1 + γ)(2l 2 + l) L(1 + 3l) + γ(2l 2 + 3l + 1)]. For ρ > 0, we need k 3 > 0. Therefore, from (43), it is noted that the proper energy density ρ(t) is a decreasing function of time and it approaches a small positive value at present epoch. From (45), it can be seen that the cosmological constant Λ is a decreasing function of time and Λ > 0 when T > T c, where T c is a critical time given by T c = 2lβ 2 a 2 (1 + 3l) + γ(2l 2 + 3l + 1) ] N 2 α(l + 2) ] l 2 α+2l 2 (46)
8 8 Bianchi type-iii cosmological model with variable G and Λ-term in general relativity 755 Fig. 1 The plot of cosmological constant Λ vs. T Fig. 2 The plot of gravitational constant G vs. T
9 756 Hassan Amirhashchi, H. Zainuddin, Anirudh Pradhan 9 This nature of Λ is clearly shown in Figure 1 as a representative case with appropriate choice of constants of integration and other physical parameters using reasonably well known situations. Also from (44), it can be seen that the gravitational constant G > 0 if N 2 ] l 2 L(l + 2) L(1+3l)+γ(2l 2 +3)] lγ(1+2l)+1] T >. (47) lβ 2 a 2 We have observed that G is an increasing function of time which can also be seen in Figure 2. The physical quantities ρ and Λ tend to infinity at T = 0 and 0 at T = whereas the gravitational constant G 0 as T 0 and as T. The model (39) therefore starts with a big-bang at T = 0 and it goes on expanding until it comes to rest at T =. We also note that T = 0 and T = respectively correspond to the proper time t = 0 and t =. There is a point type singularity (MacCallum 79]) in the model at T = 0. The expressions for the scalar of expansion θ, magnitude of shear σ 2, the average anisotropy parameter A m, deceleration parameter q and proper volume V for the model (39) are given by ( (l 1)L θ = (2l + 1)L, σ 2 = 1 lβt 3 lβt q = lβ (2l + 1), V = N 2 M m ) 2 ( ) l 1 2, A m = 2, 2l l T L(2) l. The rate of expansion H i in the direction of x, y and z are given by (48) H x = H y = L βt, H z = L lβt. (49) Hence the average generalized Hubble s parameter is given by H = L(2l + 1) 3lβT. (50) From the above results, it can be seen that the spatial volume is zero at T = 0 and it increases with the increase of T. This shows that the universe starts evolving with zero volume at T = 0 and expands with cosmic time T. From equation (49), we observe that all the three directional Hubble parameters are zero at T. In derived model, the energy density tend to infinity at T = 0. The model has the point-type singularity at T = 0. The shear scalar diverse at T = 0. As T, the scale factors A(t), B(t) and C(t) tend to infinity. The energy density becomes zero as T. The expansion scalar and shear scalar all tend to zero as T. The mean anisotropy parameter are uniform throughout whole expansion of the universe when l 1 2
10 10 Bianchi type-iii cosmological model with variable G and Λ-term in general relativity 757 but for l = 1 2 it tends to infinity. This shows that the universe is expanding with the increase of cosmic time but the rate of expansion and shear scalar decrease to zero and tend to isotropic. At the initial stage of expansion, when ρ is large, the Hubble parameter is also large and with the expansion of the universe H, θ decrease as does ρ. Since σ2 = constant provided l 1 θ 2 2, the model does not approach isotropy at any time. The cosmological evolution of Bianchi type-iii space-time is expansionary, with all the three scale factors monotonically increasing function of time. The dynamics of the mean anisotropy parameter depends on the value of l. From (48) we observe that (i) for l < 1 2, q > 0 i.e., the model is decelerating and (ii) for l > 1 2, q < 0 i.e., the model is accelerating. Moreover, it is observed that due to the combined effect of time variable Λ and G the universe evolved with deceleration as well as acceleration. Recent observations of type Ia supernovae 1 5,16] and references therein) reveal that the present universe is in accelerating phase and deceleration parameter lies somewhere in the range 1 < q 0. It follows that our model of the universe is consistent with the recent observations. 4. CONCLUDING REMARKS In this paper we have presented a new exact solution of Einstein s field equations for anisotropic Bianchi type-iii space-time in presence of perfect fluid with time varying gravitational constant G and cosmological constant Λ which is different from the other author s solutions. In general the model is expanding, shearing and nonrotating. The model starts with a big-bang at T = 0 and it goes on expanding until it comes out to rest at T =. It is worth mentioned here that T = 0 and T = correspond to the proper time t = 0 and t = respectively. The initial singularity in the model is the Point Type 79]. Our universe starts evolving with zero volume at T = 0 and expand with cosmic time T. We observe that σ2 is constant provided l 1 θ 2 2, the model does not approach isotropy at any time. Our model is in accelerating phase which is consistent to the recent observations. In some cases, it is observed that G is an increasing function of time. When the universe is required to have expanded from a finite minimum volume, the critical density assumption and conservation of energymomentum tensor dictate that G increases in a perpetually expanding universe. The possibility of an increasing G has been suggested by several authors. The behavior of the universe in our models will be determined by the cosmological term Λ ; this term has the same effect as a uniform mass density ρ eff = Λ/4πG, which is constant in time. A positive value of Λ corresponds to a negative effective mass density (repulsion). Hence, we expect that in the universe with a positive value of Λ, the expansion will tend to accelerate; whereas in the universe with negative value of Λ, the expansion will slow down, stop and reverse. In a universe with both matter and vacuum energy, there is a competition between the tendency of
11 758 Hassan Amirhashchi, H. Zainuddin, Anirudh Pradhan 11 Λ to cause acceleration and the tendency of matter to cause deceleration with the ultimate fate of the universe depending on the precise amounts of each component. This continues to be true in the presence of spatial curvature, and with a non-zero cosmological constant it is no longer true that the negatively curved ( open ) universes expand indefinitely while positively curved ( closed ) universes will necessarily recollapse-each of the four combinations of negative or positive curvature and eternal expansion or eventual re-collapse become possible for appropriate values of the parameters. There may even be a delicate balance, in which the competition between matter and vacuum energy is needed drawn and the universe is static (not expanding). The search for such a solution was Einstein s original motivation for introducing the cosmological constant. Recent cosmological observations 1 8, 16] suggest the existence of a positive cosmological constant Λ with the magnitude Λ(G /c 3 ) These observations on magnitude and red-shift of type Ia supernova suggest that our universe may be an accelerating one with induced cosmological density through the cosmological Λ-term. In our derived model, we have observed that the Λ-term decreases as time increases and it approaches to a small and positive value at the present epoch. Thus, our models are consistent with the results of recent observations. Also (14) implies that G(t) increases or decrease as Λ(t) decreases or increase. In our case, G increases as Λ decreases with time. It is also worth mention here that for l = 1, H 0 T 0 = 1 2β. For 5 13 < β < 5 8, we obtain the current limits for the universe age 0.8 < T 0H 0 < 1.3 which is in good agreement with the best estimation T 0 H 0 1 (see 61]). Thus it has been found that all physical and geometric parameter of the model (39) are in fair agreement of observational results. Acknowledgments. This work has been supported by the FRGS Grant by the Ministry of Higher Education, Malaysia under the Project Number FR. H. Amirhashchi and A. Pradhan also thank the Laboratory of Computational Sciences and Mathematical Physics, Universiti Putra Malaysia for providing facility where this work was done. REFERENCES 1. S. Perlmutter et al., Astrophys. J. 483, 565 (1997). 2. S. Perlmutter et al., Nature 391, 51 (1998). 3. S. Perlmutter et al., Astrophys. J. 517, 5 (1999). 4. A. G. Riess et al., Astron. J. 116, 1009 (1998). 5. A. G. Riess et al., Publ. Astron. Soc. Pacific (PASP) 112, 1284 (2000). 6. P. M. Garnavich et al., Astrophys. J. 493, L53 (1998). 7. P. M. Garnavich et al., Astrophys. J. 509, 74 (1998). 8. B. P. Schmidt et al., Astrophys. J. 507, 46 (1998). 9. G. Efstathiou et al., Mon. Not. R. Astron. Soc. 330, L29 (2002). 10. D. N. Spergel et al., Astrophys. J. Suppl. Ser. 148, 175 (2003).
12 12 Bianchi type-iii cosmological model with variable G and Λ-term in general relativity S. W. Allen et al., Mon. Not. R. Astron. Soc. 353, 457 (2004). 12. V. Sahni, A. A. Starobinsky, Int. J. Mod. Phys. D 9, 373 (2000). 13. P. J. E. Peebles, B. Ratra, Rev. Mod. Phys. 75, 559 (2003). 14. T. Padmanabhan, Phys. Rep. 380, 235 (2003). 15. J. A. S. Lima, J. M. F. Maia, Phys. Rev. D 49, 5579 (1994). 16. A. G. Riess et al., Astrophys. J. 607, 665 (2004). 17. R. K. Knop et al., Astrophys. J. 598, 102 (2003). 18. A. D. Dolgov, in The Very Early Universe, eds. G. W. Gibbons, S. W. Hawking, Siklos, p. 449 (S.T.C., Cambridge University Press, Cambridge, 1983). 19. W. Chen and Y. S. Wu, Phys. Rev. D 41, 695 (1990). 20. D. Pavon, Phys. Rev. D 43, 375 (1991). 21. J. C. Carvalho, J. A. S. Lima and I. Waga, Phys. Rev. D 46, 2404 (1992). 22. J. A. S. Lima and J. M. F. Maia, Phys. Rev. D 49, 5579 (1994). 23. J. A. S. Lima and M. Trodden, Phys. Rev. D 53, 4280 (1996). 24. A. I. Arbab and A.-M. M. Abdel-Rahaman, Phys. Rev. D 50, 7725 (1994). 25. R. G. Vishwakarma, Gen. Rel. Grav. 33, 1973 (2001). 26. J. V. Cunha and R. C. Santos, Int. J. Mod. Phys. D 13, 1321 (2004). 27. S. Carneiro, J. A. Lima, Int. J. Mod. Phys. A 20, 2465 (2005). 28. C. P. Singh and S. Kumar, Int. J. Theor. Phys. 47, 3171 (2008). 29. A. Pradhan, Fizika B 16, 205 (2007). 30. A. Pradhan, Fizika B 18, 61 (2009). 31. A. Pradhan, Commun. Theor. Phys. 51, 367 (2009). 32. A. Pradhan and H. R. Pandey, Int. J. Mod. Phys. D 12, 941 (2003). 33. A. Pradhan and O. P. Pandey, Int. J. Mod. Phys. D 12, 1299 (2003). 34. A. Pradhan and S. Singh, Int. J. Mod. Phys. D 13, 503 (2004). 35. A. Pradhan, V. Rai and K. Jotania, Commun. Theor. Phys. 50, 279 (2008). 36. A. Pradhan and P. Pandey, Astrophys. Space Sci. 301, 127 (2006). 37. P. S. Wesson, Gravity, Particles and Astrophysics (Reidel, Dordrecht, Holland, 1980). 38. P. A. M. Dirac, Nature (London) 139, 323 (1937). 39. P. A. M. Dirac, Nature (London) 139, 1001 (1937). 40. P. A. M. Dirac, Proc. R. Soc. 165, 199 (1938). 41. P. A. M. Dirac, The general Theory of Relativity (Wiley, New York, 1975). 42. R. H. Dicke, Nature (London) 192, 440 (1961). 43. V. M. Canuto and J. V. Narlikar, Astrophys. J. 236, 6 (1980). 44. D. Kallingas, P. S. Wesson and C. W. S. Everitt, Gen. Rel. Grav. 24, 351 (1992). 45. A.-M. M. Abdel-Rahaman, Gen. Rel. Grav. 22, 655 (1990). 46. M. S. Berman, Gen. Rel. Grav. 23, 465 (1991). 47. A. Beesham, Int. J. Theor. Phys. 25, 1295 (1986). 48. O. Bertolami, Nuovo Cimento B 93, 36 (1986). 49. O. Bertolami, Fortschr. Phys. 34, 829 (1986). 50. S. G. Turyshev et al., Lect. Notes Phys. 648, 311 (2004) arxiv:gr-qc/ ]. 51. Z. Arzoumanian, Ph. D. thesis (Princeton University Press, Princeton, New Jersey, USA, 1995). 52. V. M. Kaspi, J. H. Taylor and M. Ryba, Ap. J. 428, 713 (1994). 53. I. H. Stairs, Living Rev. Rel. 6, 5 (2003). 54. E. Gaztanaga et al., Phys. Rev. D 65, (2002).
13 760 Hassan Amirhashchi, H. Zainuddin, Anirudh Pradhan D. B. Guenther et al., Ap. J. 498, 871 (1998). 56. M. Biesiada and B. Malec, Mon. Not. R. Astron. Soc. 350, 644 (2004). 57. O. G. Benvenuto et al., Phys. Rev. D 69, (2004). 58. A. I. Arbab, J. Cosm. Astropart. Phys. 05, 008 (2003). 59. A. I. Arbab, Class. Quant. Grav. 20, 93 (2003). 60. R. F. Sistero, Gen. Rel. Grav. 23, 1265 (1991). 61. A. Sattar and R. G. Vishwakarma, Aust. J. Phys. 50, 893 (1997). 62. A. Sattar and R. G. Vishwakarma, Class. Quant. Grav. 14, 945 (1997). 63. A. Pradhan and I. Chakrabarty, Gravit. & Cosmo. 7, 239 (2001). 64. A. Pradhan and V. K. Yadav, Int. J. Mod. Phys. D 11, 893 (2002). 65. A. K. Yadav, A. Pradhan, A. K. Singh, Astrophys. Space Sci. 337, 431 (2012). 66. J. P. Singh, A. Pradhan and A. K. Singh, Astrophys. Space Sci. 314, 83 (2008). 67. C. P. Singh, S. Kumar and A. Pradhan, Class. Quantum Grav. 24, 455 (2007). 68. G. P. Singh and A. Y. Kale, Int. J. Theor. Phys. 48, 1177 (2009). 69. R. Bali and S. Tinker, Chin. Phys. Lett. 25, 3090 (2008). 70. C. P. Singh, Int. J. Theor. Phys. 45, 531 (2006). 71. D. Behera, S. K. Tripathi and T. R. Routray, Int. J. Theor. Phys. 49, 2569 (2010). 72. S. Ray, U. Mukhopadhyay and S. B. Dutta Choudhury, Int. J. Mod. Phys. D 16, 1791 (2007). 73. U. Mukhopadhyay, P. P. Ghosh and S. Ray, arxiv:gr-qc/ ] (2010). 74. A. I. Arbab, Chin. Phys. Lett. 25, 3834 (2008). 75. A. Pradhan, A. K. Singh and S. Otarod, Rom. J. Phys. 52, 445 (2007). 76. G. S. Khadekar and V. Kamdi, Rom. J. Phys. 55, 871 (2010). 77. J. P. Singh, R. K. Tiwari and P. Shukla, Chin. Phys. Lett. 24, 3325 (2007). 78. R. Bali, S. Tinker and P. Singh, Int. J. Theor. Phys. 49, 1431 (2010). 79. M. A. H. MacCallum, Comm. Math. Phys. 20, 57 (1971).
FRW UNIVERSE WITH VARIABLE G AND Λ TERM IN f(r,t ) GRAVITY
FRW UNIVERSE WITH VARIABLE G AND Λ TERM IN f(r,t ) GRAVITY G. P. SINGH a, BINAYA K. BISHI b Department of Mathematics, Visvesvaraya National Institute of Technology Nagpur, Nagpur-440010, India E-mail:
More informationA Mathematical Aspect of Higher Dimensional. Cosmological Models with Varying G and ΛTerm
Int. J. Contemp. Math. Sciences, Vol. 7, 01, no. 1, 1005-101 A Mathematical Aspect of Higher Dimensional Cosmological Models with Varying G and ΛTerm. K. Dubey Department of Mathematics, Govt. Science
More informationNEW EXACT SOLUTION OF BIANCHI TYPE V COSMOLOGICAL STIFF FLUID MODEL IN LYRA S GEOMETRY
ASTROPHYSICS NEW EXACT SOLUTION OF BIANCHI TYPE V COSMOLOGICAL STIFF FLUID MODEL IN LYRA S GEOMETRY VINEET K. YADAV 1,, LALLAN YADAV 2, ANIL KUMAR YADAV 3 1,2 Department of Physics, D. D. U. Gorahpur University,
More informationLocally-rotationally-symmetric Bianchi type-v cosmology in general relativity
PRAMANA c Indian Academy of Sciences Vol. 72, No. 2 journal of February 2009 physics pp. 429 443 Locally-rotationally-symmetric Bianchi type-v cosmology in general relativity C P SINGH Department of Applied
More informationSOME EXACT BIANCHI TYPE-I COSMOLOGICAL MODELS IN SCALAR-TENSOR THEORY OF GRAVITATION WITH TIME DEPENDENT DECELERATION PARAMETER
SOME EXACT BIANCHI TYPE-I COSMOLOGICAL MODELS IN SCALAR-TENSOR THEORY OF GRAVITATION WITH TIME DEPENDENT DECELERATION PARAMETER ANIRUDH PRADHAN 1, ANAND SHANKAR DUBEY 2, RAJEEV KUMAR KHARE 3 1 Department
More informationBianchiTypeVICosmologicalModelwithQuadraticformofTimeDependentTerminGeneralRelativity
Global Journal of Science Frontier Research: A Physics and Space Science Volume 16 Issue 6 Version 1.0 Year 2016 Type : Double Blind Peer Reviewed International Research Journal Publisher: Global Journals
More informationBianchi Type-VI0Dark Energy Cosmological Models in General Relativity
Global Journal of Science Frontier Research Mathematics and Decision Sciences Volume 12 Issue 12 Version 1.0 Type : Double Blind Peer Reviewed International Research Journal Publisher: Global Journals
More informationDYNAMIC COSMOLOGICAL CONSTANT IN BRANS DICKE THEORY
DYNAMIC COSMOLOGICAL CONSTANT IN BRANS DICKE THEORY G P SINGH, AY KALE, J TRIPATHI 3 Department of Mathematics, Visvesvaraya National Institute of Technology, Nagpur - 44, India Department of Mathematics,
More informationMagnetized Anisotropic Bianchi Type-VI Cosmological Model Containing Dark Energy
IOSR Journal of pplied Physics (IOSR-JP) e-issn: 78-486Volume 0, Issue Ver II (Jan eb 08), PP 3-35 wwwiosrjournalsorg Magnetized nisotropic Bianchi Type-VI Cosmological Model Containing Dark Energy Mukunda
More informationInternational Journal of Emerging Technologies in Computational and Applied Sciences (IJETCAS)
International Association of Scientific Innovation and Research (IASIR) (An Association Unifying the Sciences, Engineering, and Applied Research) International Journal of Emerging Technologies in Computational
More informationModified generalized Chaplygin gas model in Bianchi type-v space-time geometry with dynamical G and
Journal of Physics: Conference Series PAPER OPEN ACCESS Modified generalized Chaplygin gas model in Bianchi type-v space-time geometry with dynamical G and To cite this article: S Kotambkar et al 015 J.
More informationR. K. Tiwari & Rameshwar Singh
Role of conharmonic flatness in Friedmann cosmology R. K. Tiwari & Rameshwar Singh Astrophysics and Space Science An International Journal of Astronomy, Astrophysics and Space Science ISSN 0004-640X Volume
More informationAccelerating Dark Energy Models in Bianchi Type-V Space-Time with Time Dependent Deceleration Parameter
EJTP 9, No. 27 (2012) 159 176 Electronic Journal of Theoretical Physics Accelerating Dark Energy Models in Bianchi Type-V Space-Time with Time Dependent Deceleration Parameter Anirudh Pradhan 1, Hassan
More informationAnisotropic Dark Energy Bianchi Type III Cosmological Models in Brans Dicke Theory of Gravity
arxiv:106.0391v1 [gr-qc] Jun 01 Anisotropic Dark Energy Bianchi Type III Cosmological Models in Brans Dicke Theory of Gravity M. Farasat Shamir and Akhlaq Ahmad Bhatti Department of Sciences and Humanities,
More informationBianchi Type-III Inflationary Universe with Constant Deceleration Parameter in General Relativity
Bulg. J. Phys. 38 2011 139 1 Bianchi Type-III Inflationary Universe with Constant Deceleration Parameter in General Relativity S.D. Katore Department of Mathematics, S.G.B. Amravati University, Amravati
More informationInternational Journal of Applied and Universal Research ISSN No: Volume III, Issue II, Mar-Apr Available online at:
BIANCHI TYPE III ELECTRO MAGNETIZED COSMOLOGICAL MODEL WITH NAMBU STRINGS IN GENERAL THEORY OF RELATIVITY R.K.Dubey 1, Anil Saini 2, Neelam Yadav 3 1 Department of Mathematics, Govt. SKN PG College Mauganj
More informationHypersurface-homogeneous cosmological models with anisotropic dark energy in Saez Ballester theory of gravitation
Pramana J. Phys. (207) 88: 8 DOI 0.007/s204-06-7-4 c Indian Academy of Sciences Hypersurface-homogeneous cosmological models with anisotropic dark energy in Saez Ballester theory of gravitation MVERMA,
More informationFive Dimensional Bianchi Type V I 0 Dark Energy Cosmological Model in General Relativity
The African Review of Physics (014) 9:001 77 Five Dimensional Bianchi Type I 0 Dark Energy Cosmological Model in General Relativity B. Mishra 1, and S. K. Biswal Department of Mathematics, Birla Institute
More informationA Study of the Variable Equation-of-State Parameter in the Framework of Brans-Dicke Theory
International Journal of Pure and Applied Physics. ISSN 0973-1776 Volume 13, Number 3 (2017), pp. 279-288 Research India Publications http://www.ripublication.com A Study of the Variable Equation-of-State
More informationBIANCHI TYPE I ANISOTROPIC UNIVERSE WITHOUT BIG SMASH DRIVEN BY LAW OF VARIATION OF HUBBLE S PARAMETER ANIL KUMAR YADAV
BIANCHI TYPE I ANISOTROPIC UNIVERSE WITHOUT BIG SMASH DRIVEN BY LAW OF VARIATION OF HUBBLE S PARAMETER ANIL KUMAR YADAV Department of Physics, Anand Engineering College, Keetham, Agra -282 007, India E-mail:
More informationAnisotropic Bianchi Type-I Magnetized String Cosmological Models with Decaying Vacuum Energy Density Λ(t)
Commun. Theor. Phys. 55 011 931 941 Vol. 55, No. 5, May 15, 011 Anisotropic Bianchi Type-I Magnetized String Cosmological Models with Decaying Vacuum Energy Density Λt Anirudh Pradhan Department of Mathematics,
More informationBianchi Type VI0 Inflationary Universe with Constant Deceleration Parameter and Flat Potential in General Relativity
Advances in Astrophysics, Vol., No., May 7 https://dx.doi.org/.66/adap.7. 67 Bianchi ype VI Inflationary Universe with Constant Deceleration Parameter and Flat Potential in General Relativity Raj Bali
More informationGeometrical Behaviuors of LRS Bianchi Type-I Cosmological Model
EJTP 6, No. 22 (2009) 79 84 Electronic Journal of Theoretical Physics Geometrical Behaviuors of LRS Bianchi Type-I Cosmological Model Hassan Amirhashchi 1, Hishamuddin Zainuddin 2 and Hamid Nil Saz Dezfouli
More informationAnisotropic Lyra cosmology
PRAMANA c Indian Academy of Sciences Vol. 62, No. 6 journal of June 2004 physics pp. 87 99 B B BHOWMIK and A RAJPUT 2 Netaji Subhas Vidyaniketan Higher Secondary School, Basugaon 783 372, Dist. Kokrajhar,
More informationTheoretical Models of the Brans-Dicke Parameter for Time Independent Deceleration Parameters
Theoretical Models of the Brans-Dicke Parameter for Time Independent Deceleration Parameters Sudipto Roy 1, Soumyadip Chowdhury 2 1 Assistant Professor, Department of Physics, St. Xavier s College, Kolkata,
More informationBianchi Type VIII Inflationary Universe with Massless Scalar Field in General Relativity
August 05 Volume 6 Issue 8 pp. 679-68 Bali,. & Swati, Bianchi Type VIII Inflationary Universe with Massless Scalar Field in General elativity Bianchi Type VIII Inflationary Universe with Massless Scalar
More informationDynamics of Bianchi type-vi 0 holographic dark energy models in general relativity and Lyra s geometry
Pramana J. Phys. (2017) 88: 0 DOI 10.1007/s1204-016-18-z c Indian Academy of Sciences Dynamics of Bianchi type-vi 0 holographic dark energy models in general relativity and Lyra s geometry S D KATORE and
More informationLRS Bianchi Type I Cosmological Model with Bulk Viscosity in Lyra Geometry
Bulg. J. Phys. 4 (5 4 5 LRS Bianchi Type I Cosmological Model with Bulk Viscosity in Lyra Geometry S.P. Kandalkar, S. Samdurkar Department of Mathematics, Govt. Vidarbha Institute of Science & Humanities,
More informationA Magnetized Kantowski-Sachs Inflationary Universe in General Relativity
Bulg. J. Phys. 37 (2010) 144 151 A Magnetized Kantowski-Sachs Inflationary Universe in General Relativity S.D. Katore PG Department of Mathematics, SGB Amravati University, Amravati, India Received 10
More informationA higher-dimensional Bianchi type-i inflationary Universe in general relativity
PRAMANA c Indian Academy of Sciences Vol. 78, No. 1 journal of January 01 physics pp. 101 107 A higher-dimensional Bianchi type-i inflationary Universe in general relativity SDKATORE 1,, K S ADHAV 1, V
More informationSTRING COSMOLOGICAL MODELS IN BIANCHI TYPE-III SPACE-TIME WITH BULK VISCOSITY AND Λ TERM
Jan. 05. Vol. 6. No. 0 0-05 ES & F. ll rights reserved ISSN05-869 STIN OSMOLOIL MODELS IN BINHI TYPE-III SPE-TIME WITH BULK VISOSITY ND Λ TEM PEETI SONI SPN SHIMLI search Scholar Department of Mathematics
More informationBianchi Type-VI Bulk Viscous Fluid String Cosmological Model in General Relativity
Bulg. J. Phys. 38 2011 14 14 Bianchi Type-VI Bulk Viscous Fluid String Cosmological Model in General Relativity S.P. Kandalkar 1, P.P. Khade 2, S.P. Gawande 1 1 Department of Mathematics, Government Vidarbha
More informationarxiv:gr-qc/ v1 1 Nov 2002
International Journal of Modern Physics D, c World Scientific Publishing Company Vol. 0, No. 0 (2002 000 000 PLANE-SYMMETRIC INHOMOGENEOUS BULK VISCOUS COSMOLOGICAL MODELS WITH VARIABLEΛ arxiv:gr-qc/0211002v1
More informationString Fluid Cosmological Model with Magnetic Field in Bimetric Theory of Gravitation
Available at http://pvamu.edu/aam Appl. Appl. Math. ISSN: 1932-9466 Vol. 9, Issue 1 (June 2014), pp. 246-259 Applications and Applied Mathematics: An International Journal (AAM) String Fluid Cosmological
More informationBianchi Type-VI Inflationary Universe in General Relativity
March 01 Vol. 3 Issue 5 pp. 7-79 Katore S. D. & Chopade B. B. Bianchi Type-VI Inflationary Universe in General Relativity Bianchi Type-VI Inflationary Universe in General Relativity 7 Article Shivdas.
More informationHypersurface-homogeneous Universe filled with perfect fluid in f(r, T) theory of gravity
Pramana J. Phys. (6) 87: 83 DOI.7/s43-6-99- c Indian Academy of Sciences Hypersurface-homogeneous Universe filled with perfect fluid in f(r, T) theory of gravity A Y SHAIKH, and S D KATORE Department of
More informationSOME LRS BIANCHI TYPE-I COSMOLOGICAL MODELS WITH ZERO-MASS SCALAR FIELD
SOME LRS BIANCHI TYPE-I COSMOLOGICAL MODELS WITH ZERO-MASS SCALAR FIELD By Purushottam R.B.S. Yadav Manish Kumar Deptt. of Mathematics P.G. Deptt. of Mathematics P.G. Deptt. of Mathematics Nalanda College
More informationInternational Journal of Applied and Universal Research E-ISSN No: Volume III, Issue V, Sept-Oct Available online at:
COSMOLOGICAL MODELS BIANCHI TYPE II WITH BULK VISCOSITY IN GENERAL THEORY OF RELATIVITY R.K. Dubey 1, Shishir Kumar Srivastava 2, Dhirendra Tripathi 3 1 Department of Mathematics Govt. S.K.N.P.G. College,
More informationarxiv:gr-qc/ v1 19 May 2006
1 A late time acceleration of the universe with two scalar fields : many possibilities arxiv:gr-qc/0605110v1 19 May 2006 Narayan Banerjee and Sudipta Das Relativity and Cosmology Research Centre, Department
More information8. On wave solutions of the non-symmetric unified field theories (A. Pradhan). Rev. Mat. Fisica Teorica, Vol. XXVII (1977).
LIST OF PUBLICATIONS Anirudh Pradhan Prepared on April 30, 2010 Published Papers: 1. On wave solutions of the field equations of General Relativity containing electromagnetic field in generalized Peres-space-times
More informationNew exact cosmological solutions to Einstein s gravity minimally coupled to a Quintessence field
New exact cosmological solutions to Einstein s gravity minimally coupled to a Quintessence field Olga Arias, Tame Gonzalez and Israel Quiros Physics Department. Las Villas Central University. Santa Clara
More informationA COSMOLOGICAL MODEL WITH VARYING G AND IN GENERAL RELATIVITY
A COSMOLOGICAL MODEL WITH VARYING G AND IN GENERAL RELATIVITY Harpreet 1, R.K. Tiwari and *H.S. Sahota 1, Sant Baba Bhag Singh Institute of Engineering and Technology, Department of Applied Sciences, Khiala,
More informationViscosity Effects on Anisotropic Universe in Curvature-Matter Coupling Gravity
Commun. Theor. Phys. 69 08) 537 543 Vol. 69, No. 5, May, 08 Viscosity Effects on Anisotropic Universe in Curvature-Matter Coupling Gravity M. Sharif and Aisha Siddiqa Department of Mathematics, University
More informationSpatially Homogeneous Cosmological Models in f(r, T ) Theory of Gravity
EJTP, No. 3 (5) 69 8 Electronic Journal of Theoretical Physics Spatially Homogeneous Cosmological Models in f(r, T ) Theory of Gravity S. Chandel and Shri Ram Department of Applied Mathematics, Indian
More informationHypersurface Homogeneous Space Time with Anisotropic Dark Energy in Brans Dicke Theory of Gravitation
Commun. Theor. Phys. 62 (204 768 774 Vol. 62, No. 5, November, 204 Hypersurface Homogeneous Space Time with Anisotropic Dark Energy in Brans Dicke Theory of Gravitation S.D. Katore,, M.M. Sancheti, S.P.
More informationPLANE SYMMETRIC UNIVERSE WITH COSMIC STRING AND BULK VISCOSITY IN SCALAR TENSOR THEORY OF GRAVITATION 1. INTRODUCTION
PLANE SYMMETRIC UNIVERSE WITH COSMIC STRING AND BULK VISCOSITY IN SCALAR TENSOR THEORY OF GRAVITATION S.D. KATORE, A.Y. SHAIKH Department of Mathematics, S.G.B. Amravati University, Amravati-60, India
More informationBianchi-IX string cosmological model in Lyra geometry
PRAMANA cfl Indian Academy of Sciences Vol. 60, No. 6 journal of June 200 physics pp. 115 1159 Bianchi-IX string cosmological model in Lyra geometry F RAHAMAN 1;2, S CHAKRABORTY 2, N BEGUM 1, M HOSSAIN
More informationThe Hubble Constant and the Deceleration Parameter in Anisotropic Cosmological Spaces of Petrov type D
Advanced Studies in Theoretical Physics Vol. 10, 2016, no. 8, 421-431 HIKARI Ltd, www.m-hikari.com https://doi.org/10.12988/astp.2016.6930 The Hubble Constant and the Deceleration Parameter in Anisotropic
More informationGravitational collapse and the vacuum energy
Journal of Physics: Conference Series OPEN ACCESS Gravitational collapse and the vacuum energy To cite this article: M Campos 2014 J. Phys.: Conf. Ser. 496 012021 View the article online for updates and
More informationPlane Symmetric Universe with Λ in f(r,t) Gravity
November 05 Volume 6 Issue pp. 79-97 Shaikh, A. Y., & Bhoyar, S. R., Plane Symmetric Universe with Λ in f(r, Gravity Plane Symmetric Universe with Λ in f(r, Gravity 79 Article A. Y. Shaikh * & S. R. Bhoyar
More informationarxiv: v2 [gr-qc] 24 Nov 2014
Kaluza-Klein cosmological model in f(r, T ) gravity with Λ(T ) P.K. Sahoo, B. Mishra, S.K. Tripathy A class of Kaluza-Klein cosmological models in f(r, T ) theory of gravity have been investigated. In
More informationCanadian Journal of Physics. Anisotropic solution in phantom cosmology via Noether symmetry approach
Anisotropic solution in phantom cosmology via Noether symmetry approach Journal: Canadian Journal of Physics Manuscript ID cjp-2017-0765.r2 Manuscript Type: Article Date Submitted by the Author: 07-Dec-2017
More informationCosmic Transit and Anisotropic Models in f(r,t) Gravity
1 Cosmic Transit and Anisotropic Models in f(r,t) Gravity S.K. Sahu, S.K.Tripathy, P.K. Sahoo, A. Nath arxiv:1611.03476v2 [gr-qc] 20 Jun 2017 Abstract Accelerating cosmological models are constructed in
More informationBianchi Type V Magnetized String Dust Universe with Variable Magnetic Permeability
EJTP 5, No. 19 (008) 105 114 Electronic Journal of Theoretical Physics Bianchi Type V Magnetized String Dust Universe with Variable Magnetic Permeability Raj Bali Department of Mathematics, University
More informationThe early and late time acceleration of the Universe
The early and late time acceleration of the Universe Tomo Takahashi (Saga University) March 7, 2016 New Generation Quantum Theory -Particle Physics, Cosmology, and Chemistry- @Kyoto University The early
More informationBianchi Type-IX Bulk Viscous String Cosmological Model in f(r,t) Gravity with Special Form of Deceleration Parameter
International Journal of heoretical and Mathematical Physics 0, (6): 0-7 DOI: 0593/jijtmp00060 Bianchi ype-ix Bul Viscous String Cosmological Model in f(r,) Gravity with Special Form of Deceleration Parameter
More informationarxiv: v1 [gr-qc] 22 Apr 2008
Noether symmetry in f(r) cosmology Babak Vakili Department of Physics, Shahid Beheshti University, Evin, Tehran 19839, Iran June 6, 008 arxiv:0804.3449v1 [gr-qc] Apr 008 Abstract The Noether symmetry of
More informationDARK ENERGY COSMOLOGICAL MODEL FOR BIANCHI TYPE III SPACE-TIME WITH PERFECT FLUID
International Journal of Pure and Applied Mathematics Volume 99 No. 1 2015, 109-121 ISSN: 1311-8080 (printed version); ISSN: 1314-3395 (on-line version) url: http://www.ijpam.eu doi: http://dx.doi.org/10.12732/ijpam.v99i1.9
More informationarxiv: v2 [gr-qc] 25 Jan 2010
Astrophysics and Space Science DOI 10.1007/s - - - de Sitter expansion with anisotropic fluid in Bianchi type-i space-time Özgür Akarsu 1 Can Battal Kılınç arxiv:1001.0550v [gr-qc] 5 Jan 010 c Springer-Verlag
More informationCanadian Journal of Physics. FLRW Cosmology of Induced Dark Energy Model and Open Universe
Canadian Journal of Physics FLRW Cosmology of Induced Dark Energy Model and Open Universe Journal: Canadian Journal of Physics Manuscript ID cjp-2016-0827.r3 Manuscript Type: Article Date Submitted by
More informationarxiv:gr-qc/ v1 9 Aug 2006
Nonlinear spinor field in Bianchi type-i cosmology: accelerated regimes Bijan Saha arxiv:gr-qc/0608047v1 9 Aug 2006 Laboratory of Information Technologies Joint Institute for Nuclear Research, Dubna 141980
More informationThermodynamics and emergent universe
Thermodynamics and emergent universe Saumya Ghosh a, Sunandan Gangopadhyay a,b a Indian Institute of Science Education and Research Kolkata Mohanpur 741246, Nadia, West Bengal, India b Visiting Associate
More informationarxiv:gr-qc/ v1 20 May 2005
EMERGENT UNIVERSE IN STAROBINSKY MODEL arxiv:gr-qc/0505103v1 20 May 2005 S. Mukherjee and B.C. Paul Physics Department, North Bengal University Dist : Darjeeling, PIN : 734 430, India. S. D. Maharaj Astrophysics
More informationRealistic Decelerating Cosmology and the Return to Contraction
Realistic Decelerating Cosmology and the Return to Contraction N.S. Baaklini nsbqft@aol.com http://www.vixra.org/author/n s baaklini Abstract For cosmological theory without the bizarre vacuum-driven acceleration,
More informationThermodynamics in modified gravity Reference: Physics Letters B 688, 101 (2010) [e-print arxiv: [gr-qc]]
Thermodynamics in modified gravity Reference: Physics Letters B 688, 101 (2010) [e-print arxiv:0909.2159 [gr-qc]] HORIBA INTERNATIONAL CONFERENCE COSMO/CosPA 2010 Hongo campus (Koshiba Hall), The University
More informationarxiv:gr-qc/ v3 21 Jul 2006
PLANE SYMMETRIC INHOMOGENEOUS BULK VISCOUS DOMAIN WALL IN LYRA GEOMETRY ANIRUDH PRADHAN 1, VANDANA RAI and SAEED OTAROD arxiv:gr-qc/0508087v3 21 Jul 2006 Department of Mathematics, Hindu Post-graduate
More informationarxiv: v2 [gr-qc] 1 Oct 2009
On the cosmological effects of the Weyssenhoff spinning fluid in the Einstein-Cartan framework Guilherme de Berredo-Peixoto arxiv:0907.1701v2 [gr-qc] 1 Oct 2009 Departamento de Física, ICE, Universidade
More informationPHYM432 Relativity and Cosmology 17. Cosmology Robertson Walker Metric
PHYM432 Relativity and Cosmology 17. Cosmology Robertson Walker Metric Cosmology applies physics to the universe as a whole, describing it s origin, nature evolution and ultimate fate. While these questions
More informationHolographic unification of dark matter and dark energy
Holographic unification of dark matter and dark energy arxiv:1101.5033v4 [hep-th] 2 Feb 2011 L.N. Granda Departamento de Fisica, Universidad del Valle, A.A. 25360 Cali, Colombia Departamento de Fisica,
More informationarxiv: v1 [gr-qc] 22 Jul 2015
Spinor Field with Polynomial Nonlinearity in LRS Bianchi type-i spacetime Bijan Saha arxiv:1507.06236v1 [gr-qc] 22 Jul 2015 Laboratory of Information Technologies Joint Institute for Nuclear Research 141980
More informationarxiv: v3 [gr-qc] 24 Mar 2014
Accelerating universe with time variation of G and Λ F. Darabi Department of Physics Azarbaijan University of Tarbiat Moallem, Tabriz, 53714-161 Iran. arxiv:0802.0028v3 [gr-qc] 24 Mar 2014 Research Institute
More informationarxiv:gr-qc/ v1 6 Nov 2006
Different faces of the phantom K.A. Bronnikov, J.C. Fabris and S.V.B. Gonçalves Departamento de Física, Universidade Federal do Espírito Santo, Vitória, ES, Brazil arxiv:gr-qc/0611038v1 6 Nov 2006 1. Introduction
More informationHolographic Ricci dark energy and generalized second law
Holographic Ricci dark energy and generalized second law arxiv:1311.4661v2 [gr-qc] 20 Nov 2013 Titus K Mathew and Praseetha P Department of Physics, Cochin University of Science and Technology, Kochi-682022,
More informationFRW models in the conformal frame of f(r) gravity
Journal of Physics: Conference Series FRW models in the conformal frame of fr gravity To cite this article: J Miritzis 2011 J. Phys.: Conf. Ser. 283 012024 View the article online for updates and enhancements.
More informationNew Non-Diagonal Singularity-Free Cosmological Perfect-Fluid Solution
New Non-Diagonal Singularity-Free Cosmological Perfect-Fluid Solution arxiv:gr-qc/0201078v1 23 Jan 2002 Marc Mars Departament de Física Fonamental, Universitat de Barcelona, Diagonal 647, 08028 Barcelona,
More informationarxiv:gr-qc/ v2 28 Nov 2005
Derivation of the Raychaudhuri Equation arxiv:gr-qc/0511123v2 28 Nov 2005 Naresh Dadhich Inter-University Centre for Astronomy & Astrophysics, Post Bag 4, Pune 411 007, India E-mail: nkd@iucaa.ernet.in
More informationExamining the Viability of Phantom Dark Energy
Examining the Viability of Phantom Dark Energy Kevin J. Ludwick LaGrange College 12/20/15 (11:00-11:30) Kevin J. Ludwick (LaGrange College) Examining the Viability of Phantom Dark Energy 12/20/15 (11:00-11:30)
More informationEvolution of holographic dark energy with interaction term Q Hρ de and generalized second law
PRAMANA c Indian Academy of Sciences Vol. 86, No. 3 journal of March 016 physics pp. 701 71 Evolution of holographic dark energy with interaction term Q Hρ de and generalized second law P PRASEETHA and
More informationRelativity, Gravitation, and Cosmology
Relativity, Gravitation, and Cosmology A basic introduction TA-PEI CHENG University of Missouri St. Louis OXFORD UNIVERSITY PRESS Contents Parti RELATIVITY Metric Description of Spacetime 1 Introduction
More informationCosmology: An Introduction. Eung Jin Chun
Cosmology: An Introduction Eung Jin Chun Cosmology Hot Big Bang + Inflation. Theory of the evolution of the Universe described by General relativity (spacetime) Thermodynamics, Particle/nuclear physics
More informationSome Bianchi Type Cosmological Models in f(r) Gravity
arxiv:1006.4249v1 [gr-qc] 22 Jun 2010 Some Bianchi Type Cosmological Models in f(r) Gravity M. arasat Shamir Department of Mathematics, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590, Pakistan.
More informationAstr 2320 Tues. May 2, 2017 Today s Topics Chapter 23: Cosmology: The Big Bang and Beyond Introduction Newtonian Cosmology Solutions to Einstein s
Astr 0 Tues. May, 07 Today s Topics Chapter : Cosmology: The Big Bang and Beyond Introduction Newtonian Cosmology Solutions to Einstein s Field Equations The Primeval Fireball Standard Big Bang Model Chapter
More informationReconstructed standard model of cosmology in the Earth-related coordinate system
Reconstructed standard model of cosmology in the Earth-related coordinate system Jian-Miin Liu Department of Physics, Nanjing University Nanjing, The People s Republic of China On leave. E-mail: liu@phys.uri.edu
More informationarxiv:astro-ph/ v3 31 Mar 2006
astro-ph/61453 Observational constraints on the acceleration of the Universe Yungui Gong College of Electronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 465, China and
More informationSergei D. Odintsov (ICREA and IEEC-CSIC) Misao Sasaki (YITP, Kyoto University and KIAS) Presenter : Kazuharu Bamba (KMI, Nagoya University)
Screening scenario for cosmological constant in de Sitter solutions, phantom-divide crossing and finite-time future singularities in non-local gravity Reference: K. Bamba, S. Nojiri, S. D. Odintsov and
More informationIntroduction to Cosmology
Introduction to Cosmology João G. Rosa joao.rosa@ua.pt http://gravitation.web.ua.pt/cosmo LECTURE 2 - Newtonian cosmology I As a first approach to the Hot Big Bang model, in this lecture we will consider
More informationarxiv:astro-ph/ v3 2 Dec 2004
Phantom-like GCG and the constraints of its parameters via cosmological dynamics Jiangang Hao Shanghai United Center for Astrophysics (SUCA), Shanghai Normal University, 100 Guilin Road, Shanghai 200234,
More informationarxiv:gr-qc/ v5 2 Mar 2006
Acceleration of the universe in the Einstein frame of a metric-affine f(r) gravity arxiv:gr-qc/0510007v5 2 Mar 2006 Nikodem J. Pop lawski Department of Physics, Indiana University, 727 East Third Street,
More informationNonhomogeneity driven Universe acceleration arxiv: v1 [astro-ph] 15 Feb 2008
Nonhomogeneity driven Universe acceleration arxiv:0802.2284v1 [astro-ph] 15 Feb 2008 Jerzy Stelmach and Izabela Jakacka Institute of Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin, Poland
More informationAddendum: Symmetries of the. energy-momentum tensor
Addendum: Symmetries of the arxiv:gr-qc/0410136v1 28 Oct 2004 energy-momentum tensor M. Sharif Department of Mathematics, University of the Punjab, Quaid-e-Azam Campus Lahore-54590, PAKISTAN. Abstract
More informationLate-time oscillatory behaviour for self-gravitating scalar fields
arxiv:gr-qc/0611088 v2 27 Nov 2006 Late-time oscillatory behaviour for self-gravitating scalar fields Alan D. Rendall Max-Planck-Institut für Gravitationsphysik Albert-Einstein-Institut Am Mühlenberg 1
More informationInternational Journal of Science and Research (IJSR) ISSN (Online): Index Copernicus Value (2013): 6.14 Impact Factor (2014): 5.
ISSN (Online): 319-7064 Index Copernicus Value (013): 6.14 Impact Factor (014): 5.611 A Study of Transition of the Expansion of the Universe from a Phase of Deceleration to Acceleration through a Conversion
More informationSpherical "Top-Hat" Collapse in a Modified Chaplygin Gas Dominated Universe
Spherical "Top-Hat" Collapse in a Modified Chaplygin Gas Dominated Universe S. Karbasi (1) and H. Rami () Department of Physics, the University of Qom, 3716146611, Qom, I. R. Iran (1) s.karbasi@stu.qom.ac.ir
More informationarxiv: v2 [gr-qc] 27 Apr 2013
Free of centrifugal acceleration spacetime - Geodesics arxiv:1303.7376v2 [gr-qc] 27 Apr 2013 Hristu Culetu Ovidius University, Dept.of Physics and Electronics, B-dul Mamaia 124, 900527 Constanta, Romania
More informationTa-Pei Cheng PCNY 9/16/2011
PCNY 9/16/2011 Ta-Pei Cheng For a more quantitative discussion, see Relativity, Gravitation & Cosmology: A Basic Introduction (Oxford Univ Press) 2 nd ed. (2010) dark matter & dark energy Astronomical
More informationQuintessence and scalar dark matter in the Universe
Class. Quantum Grav. 17 (2000) L75 L81. Printed in the UK PII: S0264-9381(00)50639-X LETTER TO THE EDITOR Quintessence and scalar dark matter in the Universe Tonatiuh Matos and L Arturo Ureña-López Departamento
More informationStability of Stellar Filaments in Modified Gravity Speaker: Dr. Zeeshan Yousaf Assistant Professor Department of Mathematics University of the Punjab
Stability of Stellar Filaments in Modified Gravity Speaker: Dr. Zeeshan Yousaf Assistant Professor Department of Mathematics University of the Punjab Lahore-Pakistan Hot Topics in Modern Cosmology, XIIth
More informationarxiv: v1 [gr-qc] 16 Aug 2011
Massless particle creation in a f(r) accelerating universe S. H. Pereira and J. C. Z. Aguilar Universidade Federal de Itajubá, Campus Itabira Rua São Paulo, 377 35900-373, Itabira, MG, Brazil arxiv:1108.3346v1
More informationCosmic Strings in Dilaton Gravity and in Brans-Dicke Theory
Bulg. J. Phys. 32 (2005) 257 262 Cosmic Strings in Dilaton Gravity and in Brans-Dicke Theory F. Rahaman, K. Gayen and A. Ghosh Dept. of Mathematics, Jadavpur University, Kolkata-700032, India Received
More information5-dimensional Brans-Dicke Theory and Cosmic Acceleration
5-dimensional Brans-Dicke Theory and Cosmic Acceleration arxiv:gr-qc/0411066v Feb 005 Li-e Qiang, Yongge Ma, Muxin Han, Dan Yu, Department of Physics, Beijing Normal University, Beijing, 100875, China
More information