Cosmology of unimodular Born-Infeld-$f(R)$ gravity

Abstract

We propose a novel modified gravity: unimodular generalization of the Born-Infeld-$f(R)$ gravity within the framework of cosmology. After formulating the action corresponding to the generalized Born-Infeld-$f(R)$ gravity, we present a reconstruction scheme of this unimodular extension to achieve various cosmological eras of the universe. Interestingly, the unimodular generalization of Born-Infeld-$f(R)$ gravity proves to be suitable for inflation (de-Sitter and quasi de-Sitter) along with power law cosmology which actually includes from reheating to the Standard Big-Bang cosmology. Apart from the inflation, such generalized Born-Infeld-$f(R)$ theory is also capable to trigger non-singular bouncing cosmology for suitable forms of the unimodular Lagrange multiplier, which are exotic for the standard Einstein-Hilbert gravity and cannot be realized in that case. The possible consequences are discussed.