Abstract
This work dedicated to the investigation cosmological models based on tachyon field. It was showed that Einstein’s field equations for spatially flat, homogeneous and isotropic Friedman-Robertson-Walker space-time have form-invariance of symmetry, obtained by form-invariance of transformations. The form-invariance of transformations is specified in the general case by the linear function 𝜌̅= 𝑛 2𝜌, and in particular, we investigate for 𝑛 = −1. The tachyonization of the cosmological model was made for the entire range of values of the barotropic index 𝛾. For the power-law function of the scale factor, a method for obtaining the potential and the function of the tachyon field was shown. The resulting potential is equivalent to the potential used in string theory.