Abstracts
Dragoljub Dimitrijevic
Tachyon scalar field in DBI and RSII cosmological context
The role tachyon fields may play in evolution of early universe is discussed.
We consider the evolution of a flat and homogeneous universe governed by a tachyon scalar field with the DBItype action and calculate the slowroll parameters of inflation, scalar spectral index and tensorscalar ratio for several models. We compare the available results obtained by analytical and numerical methods with those obtained by observation.
The possibility that influence of the radion field can extend a range of the acceptable values of the parameters came form the string theory motivated is also considered in the RSII model.
We conclude our consideration with discussion of possibilities for and consequences of "linearization" of DBI tachyon action at archimedean and nonarchimedean spaces.
References:
 N. Bilic, D.D. Dimitrijevic, G.S. Djordjevic and M. Milosevic, Int. Jour. Mod. Phys. A, 32 (2017) 1750039.
 M. Milosevic, D.D. Dimitrijevic, G.S. Djordjevic and M.D. Stojanovic, Serb. Astron. Jour., 192 (2016) 18.
 G.S. Djordjevic, D.D. Dimitrijevic and M. Milosevic, Rom. Jour. Phys., 61 (2016) 99109.
