Some cosmological and astrophysical aspects of modified gravity theories

Understand

This thesis will try to contribute to the understanding of open issues in cosmology by considering f(R) and brane-world theories.

• In Chapter 1, we shall summarize the main features of f(R) gravities in the metric formalism and we shall introduce both the notion of brane excitations, the branons, and the brane-skyrmions.
• We shall finish the chapter by providing some insight about the possibility of mini black holes detection in the LHC as a signature for the validity of these modified gravity theories.
• The Chapter 2 will deal with f(R) theories able to mimic Einstein-Hilbert plus cosmological constant solutions and f(R) theories will be shown to be able to mimic the cosmological evolution generated by any perfect fluid with constant equation of state.