Chameleon cosmology: the nonminimal coupling function from the observational data
Keywords:
chameleon cosmology, scalar fieldAbstract
Using the cosmological and astronomical observational data, the general expression for the nonminimal coupling function between a scalar field and matter (ordinary and/or dark) is obtained within the framework of chameleon cosmology. The scalar field is assumed to be homogeneously and isotopically distributed over spacetime. The effective mass of the scalar field is taken to be small on cosmological scales, but it increases in the dense environment (on Earth). This allows the laboratory tests and experiments in the solar system to be satisfied. The expansion rate of the present Universe is approximated by the Hubble parameter, which is chosen here using the model “cosmological -term plus cold dark matter”. In the case of massless scalar field, for such an ansatz the analytical expression for valid for the present Universe is found.
References
2. Copeland E. J., Sami M. and Tsujikawa S. Dynamics of dark energy // Int. J. Mod. Phys. -2006. -V. D15. -P.1753-1936.
3. De Felice A. and Tsujikawa S. f(R) theories // Living Rev. Rel. -2010. –V. 13. –P. 3-127.
4. Nojiri S. 'i. and Odintsov S. D. Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models // Phys. Rept. -2011. –V. 505. –P. 59-144.
5. Maartens R. Brane world gravity // Living Rev. Rel. -2004. –V. 7. –P. 7-61.
6. Dzhunushaliev V., Folomeev V. and Minamitsuji M. Thick brane solutions // Rept. Prog. Phys. -2010. -V. 73:066901 -29 p.
7. Khoury J. and Weltman A. Chameleon fields: Awaiting surprises for tests of gravity in space // Phys. Rev. Lett. -2004. -V. 93:171104. - 4 p.
8. Khoury J. and Weltman A. Chameleon cosmology // Phys. Rev. -2004. -V. D69:044026. -15p.
9. Brax P., van de Bruck C., Davis A. -C., Khoury J., and Weltman A. Detecting dark energy in orbit - The Cosmological chameleon // Phys. Rev. -2004. -V. D70:123518. - 18 p.
10. Dzhunushaliev V., Folomeev V. and Singleton D. Chameleon stars // Phys. Rev. -2011. -V. D84:084025. -25 p.
11. Folomeev V. Nonrelativistic isothermal fluid in the presence of a chameleon scalar field: static and collapsing configurations // Phys. Rev. -2012. -V. D85:024008. -13 p.
12. Folomeev V. and Singleton D. Relativistic polytropic spheres embedded in a chameleon scalar field // Phys. Rev. -2012. -V. D85:064045. -13 p.
13. Mota D. F. and Shaw D. J. Evading Equivalence Principle Violations, Cosmological and other Experimental Constraints in Scalar Field Theories with a Strong Coupling to Matter // Phys. Rev. -2007. -V. D75:063501. - 13 p.
14. Farajollahi H. and Salehi A. Cosmic Dynamics in the Chameleon Cosmology // Int. J. Mod. Phys. -2010. -V. D19. -P.621-633.
15. Cannata F.and Kamenshchik A. Y. Chameleon Cosmology Model Describing the Phantom Divide Line Crossing // Int. J. Mod. Phys. -2011. -V. D20. -P.121-131.
16. Chattopadhyay S. and Debnath U. Emergent universe in chameleon, f(R) and f(T) gravity theories // Int. J. Mod. Phys.-2011. -V. D20. -P.1135-1149.
17. Folomeev V. Chameleon stars supported by a cosmological scalar field // Phys. Rev. -2012. -V. D86:063008. -11 p.
18. Bertolami O., Lobo F. S. N. and Paramos J. Non-minimum coupling of perfect fluids to curvature // Phys. Rev. -2008. -V. D78:064036. -6 p.
19. Sotiriou T. P. and Faraoni V. Modified gravity with R-matter couplings and (non-)geodesic motion // Class. Quant. Grav. -2008. –V. 25: 205002. 12 p.
20. Muller C. M. Cosmological bounds on the equation of state of dark matter // Phys. Rev. -2005. -V. D71:047302. -4 p.
21. Bharadwaj S. and Kar S. Modeling galaxy halos using dark matter with pressure // Phys. Rev. -2003. -V. D68:023516. -13 p.
