Conformal transformations in cosmology of modified gravity: the covariant approach perspective
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Abstract
The 1+3 covariant approach and the covariant gauge-invariant approach to perturbations are used to analyze in depth conformal transformations in cosmology. Such techniques allow us to obtain insights on the physical meaning of these transformations when applied to non-standard gravity. The results obtained lead to a number of general conclusions on the change of some key quantities describing any two conformally related cosmological models. For example, even if some of the geometrical properties of the cosmology are preserved (homogeneous and isotropic Universes are mapped into homogeneous and isotropic universes), it can happen that decelerating cosmologies can be mapped into accelerated ones. From the point of view of the cosmological perturbations it is shown how these fluctuation transform. We find that first-order vector and tensor perturbations equations are left unchanged in their structure by the conformal transformation, but this cannot be said of the scalar perturbations, which present differences in their evolutionary features. The results obtained are then explicitly interpreted and verified with the help of some clarifying examples based on f(R)-gravity cosmologies.
Keywords
Conformal transformations Modified gravity Cosmology 1+3 Covariant approach Covariant gauge invariant theory of perturbationsPreview
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References
- 1.Bateman H. (1910) Lond. M. S. Proc. 8(2): 223–264CrossRefGoogle Scholar
- 2.Kastrup H.A. (2008) Annalen Phys. 17: 631 arXiv:0808.2730 [physics.hist-ph]MATHCrossRefADSGoogle Scholar
- 3.Synge J.L. (1960) Relativity: The General Theory. North-Holland, AmsterdamMATHGoogle Scholar
- 4.Hawking S.W., Ellis G.F.R. (1973) The Large Scale Structure of Space-Time. Cambridge University Press, CambridgeMATHCrossRefGoogle Scholar
- 5.Nojiri, S., Odintsov, S.D.: eConf C0602061, 06 (2006) [Int. J. Geom. Meth. Mod. Phys. 4, 115 (2007)] arXiv:hep-th/0601213; Nojiri, S., Odintsov, S.D.: arXiv:0807.0685 [hep-th]Google Scholar
- 6.Capozziello S., Francaviglia M. (2008) Gen. Relativ. Gravit. 40: 357 arXiv:0706.1146 [astro-ph]MATHCrossRefMathSciNetADSGoogle Scholar
- 7.Sotiriou, T.P., Faraoni, V.: arXiv:0805.1726 [gr-qc]Google Scholar
- 8.Wands D. (1994) Class. Quant. Grav. 11: 269 arXiv:gr-qc/9307034CrossRefMathSciNetADSGoogle Scholar
- 9.Maeda K.I. (1989) Phys. Rev. D 39: 3159CrossRefMathSciNetADSGoogle Scholar
- 10.Magnano G., Sokolowski L.M. (1994) Phys. Rev. D 50: 5039 arXiv:gr-qc/9312008CrossRefMathSciNetADSGoogle Scholar
- 11.Flanagan E.E. (2004) Class. Quant. Grav. 21: 3817 arXiv:gr-qc/0403063MATHCrossRefMathSciNetADSGoogle Scholar
- 12.Sotiriou T.P., Faraoni V., Liberati S. (2008) Int. J. Mod. Phys. D 17: 399 arXiv:0707.2748 [gr-qc]MATHCrossRefMathSciNetADSGoogle Scholar
- 13.Capozziello S., Nojiri S., Odintsov S.D., Troisi A. (2006) Phys. Lett. B 639: 135 arXiv:astro-ph/0604431CrossRefADSGoogle Scholar
- 14.Cotsakis S. (2008) Grav. Cosmol. 14: 176 arXiv:gr-qc/0408095MATHCrossRefMathSciNetADSGoogle Scholar
- 15.Dabrowski M.P., Garecki J., Blaschke D.B. (2009) Annalen Phys. 18: 13 arXiv:0806.2683 [gr-qc]MATHCrossRefMathSciNetADSGoogle Scholar
- 16.Ehlers, J.: Akad. Wiss. Lit. Mainz, Abhandl. Math.-Nat. Kl. 11, 793 (1961). Translation: Ehlers, J.: Gen. Relativ. Gravit. 25, 1225 (1993)Google Scholar
- 17.Ellis, G.F.R., van Elst, H.: Cargèse Lectures 1998. In: Lachièze-Rey, M. (ed.) Theoretical and Observational Cosmology, vol. 1. Kluwer, Dordrecht (1999). arXiv:gr-qc/9812046Google Scholar
- 18.Wainwright, J., Ellis, G.F.R. (eds) (1997) Dynamical Systems in Cosmology. Cambridge University Press, CambridgeGoogle Scholar
- 19.Carloni S., Dunsby P.K.S., Capozziello S., Troisi A. (2005) Class. Quant. Grav. 22: 4839 arXiv:gr-qc/0410046MATHCrossRefMathSciNetADSGoogle Scholar
- 20.Carloni, S., Troisi, A., Dunsby, P.K.S.: Gen. Relativ. Gravit. (accepted). arXiv:0706.0452 [gr-qc]Google Scholar
- 21.Carloni, S., Capozziello, S., Leach, J.A., Dunsby, P.K.S.: Class. Quant. Grav. 25, 035008 (2008). arXiv:gr-qc/0701009Google Scholar
- 22.Bardeen J.M. (1980) Phys. Rev. D 22: 1982CrossRefMathSciNetADSGoogle Scholar
- 23.Mukhanov V.F., Feldman H.A., Brandenberger R.H. (1992) Phys. Rept. 215: 203CrossRefMathSciNetADSGoogle Scholar
- 24.Kodama H., Sasaki M. (1984) Prog. Theor. Phys. Suppl. 78: 1CrossRefADSGoogle Scholar
- 25.Bruni M., Dunsby P.K.S., Ellis G.F.R. (1992) Ap. J. 395: 34CrossRefADSGoogle Scholar
- 26.Ellis G.F.R., Bruni M. (1989) Phys. Rev. D 40: 1804CrossRefMathSciNetADSGoogle Scholar
- 27.Ellis G.F.R., Bruni M., Hwang J. (1990) Phys. Rev. D 42: 1035CrossRefMathSciNetADSGoogle Scholar
- 28.Dunsby P.K.S., Bruni M., Ellis G.F.R. (1992) Astrophys. J. 395: 54CrossRefADSGoogle Scholar
- 29.Bruni M., Ellis G.F.R., Dunsby P.K.S. (1992) Class. Quant. Grav. 9: 921MATHCrossRefMathSciNetADSGoogle Scholar
- 30.Carloni S., Dunsby P.K.S., Troisi A. (2008) Phys. Rev. D 77: 024024 arXiv:0707.0106 [gr-qc]CrossRefMathSciNetADSGoogle Scholar
- 31.Ananda, K.N., Carloni, S., Dunsby, P.K.S.: arXiv:0809.3673 [astro-ph]Google Scholar
- 32.Pogosian L., Silvestri A. (2008) Phys. Rev. D 77: 023503 arXiv:0709.0296 [astro-ph]CrossRefADSGoogle Scholar
- 33.Tsujikawa S., Uddin K., Tavakol R. (2008) Phys. Rev. D 77: 043 arXiv:0712.0082 [astro-ph]MathSciNetGoogle Scholar
- 34.Tsujikawa S. (2007) Phys. Rev. D 76: 023514 arXiv:0705.1032[astro-ph]CrossRefMathSciNetADSGoogle Scholar
- 35.Li B., Barrow J.D., Mota D.F., Zhao H. (2008) Phys. Rev. D 78: 064021 arXiv:0805.4400 [gr-qc]CrossRefADSGoogle Scholar
- 36.Song Y.S., Hu W., Sawicki I. (2007) Phys. Rev. D 75: 044004 arXiv:astro-ph/0610532CrossRefMathSciNetADSGoogle Scholar
- 37.Bertschinger E., Zukin P. (2008) Phys. Rev. D 78: 024015 arXiv:0801.2431 [astro-ph]CrossRefADSGoogle Scholar
- 38.Hu W., Sawicki I. (2007) Phys. Rev. D 76: 104043 arXiv:0708.1190[astro-ph]CrossRefADSGoogle Scholar
- 39.Nesseris S. (2009) Phys. Rev. D 79: 044015 arXiv:0811.4292[astro-ph]CrossRefADSGoogle Scholar
- 40.de la Cruz-Dombriz A., Dobado A., Maroto A.L. (2008) Phys. Rev. D 77: 123515 arXiv:0802.2999 [astro-ph]CrossRefADSGoogle Scholar
- 41.Motohashi, H., Starobinsky, A.A., Yokoyama, J.: arXiv:0905.0730 [astro-ph.CO]Google Scholar
- 42.De Felice, A., Suyama, T.: arXiv:0904.2092 [astro-ph.CO]Google Scholar
- 43.Chiba, T., Yamaguchi, M.: JCAP 0810, 021 (2008) [arXiv:0807.4965]; JCAP 0901, 019 (2009) [arXiv:0810.5387]Google Scholar
- 44.Wald, R.M.: General Relativity, 491 pp. University Press, Chicago, USA (1984)Google Scholar
- 45.Faraoni V., Gunzig E., Nardone P. (1999) Fund. Cosmic Phys. 20: 121 arXiv:gr-qc/9811047ADSGoogle Scholar
- 46.Birrell N.D., Davies P.C.W. (1982) Quantum Fields in Curved Space. Cambridge University Press, CambridgeMATHGoogle Scholar
- 47.Magnano G. (1990) J. Math. Phys. 31: 378MATHCrossRefMathSciNetADSGoogle Scholar
- 48.Magnano G., Ferraris M., Francaviglia M. (1990) Class. Quant. Grav. 7: 557MATHCrossRefMathSciNetADSGoogle Scholar
- 49.Nojiri S., Odintsov S.D. (2003) Phys. Rev. D 68: 123512 arXiv:hep-th/0307288CrossRefMathSciNetADSGoogle Scholar
- 50.Capozziello, S., Carloni, S., Troisi, A.: In: Recent Research Developments in Astronomy & Astrophysics—RSP/AA/21 (2003). arXiv:astro-ph/0303041Google Scholar
- 51.Plebanski, J., Krasinski, A.: An Introduction to General Relativity and Cosmology, 534 pp. University Press, Cambridge, UK (2006)Google Scholar
- 52.Briscese F., Elizalde E., Nojiri S., Odintsov S.D. (2007) Phys. Lett. B 646: 105 arXiv:hep-th/0612220CrossRefADSGoogle Scholar
- 53.Bamba, K., Geng, C.Q., Nojiri, S., Odintsov, S.D.: arXiv:0810.4296 [hep-th]Google Scholar
- 54.Stewart, J.M.: Perturbations of Friedmann– Robertson– Walker cosmological models. Class. Quantum Grav. Class. Quant. Grav. 7 1169 (1990)Google Scholar
- 55.Abdelwahab M., Carloni S., Dunsby P.K.S. (2008) Class. Quant. Grav. 25: 135002 arXiv:0706.1375 [gr-qc]CrossRefMathSciNetADSGoogle Scholar
- 56.Nojiri S., Odintsov S.D. (2008) Phys. Rev. D 77: 026007 arXiv:0710.1738 [hep-th]CrossRefMathSciNetADSGoogle Scholar
- 57.Cognola G., Elizalde E., Nojiri S., Odintsov S.D., Sebastiani L., Zerbini S. (2008) Phys. Rev. D 77: 046009 arXiv:0712.4017[hep-th]CrossRefADSGoogle Scholar
- 58.Cognola G., Elizalde E., Odintsov S.D., Tretyakov P., Zerbini S. (2009) Phys. Rev. D 79: 044001 arXiv:0810.4989 [gr-qc]CrossRefADSGoogle Scholar
- 59.Sachs M. (1967) Synthese 17: 29CrossRefGoogle Scholar
- 60.Boniolo G., de Felice F. (2000) Found. Phys. 30: 1629CrossRefMathSciNetGoogle Scholar