A Toy Model for Accelerated Expansion of the Universe and the Modified Gravity
Qiankai Yao · Journal of Zhengzhou University · 2006
The modification of Einstein gravity theory at large scale is a kind of attractive version of the accelerated expansion of the universe at present,without the assumption of mysterious dark energy.A toy model which is compatible with the current astrophysical data and can avoid Big Rip of the universe is proposed.By substituting the scale factor of the universe,a(t),into the cosmic-dynamical equations derived from modified gravity with undetermined additional terms,then expanding the resultant equations into Taylor series with respect to t at t_0 and only taking the first two terms,the coefficient additional terms are determined.Thus,the additional modified terms are put on a more reliable basis.