Little Rip, ΛCDM and singular dark energy cosmology from Born–Infeld-f(R)f(R) gravity

We study late-time cosmic accelerating dynamics from Born–Infeld-f(R)f(R) gravity in a simplified conformal approach. We find that a variety of cosmic effects such as Little Rip, ΛCDM universe and dark energy cosmology with finite-time future singularities may occur. Unlike the convenient Born–Infeld gravity where in the absence of matter only de Sitter expansion may emerge, apparently any FRW cosmology maybe reconstructed from this conformal version of the Born–Infeld-f(R)f(R) theory. Despite the fact that the explicit form of f(R)f(R) is fixed by the conformal ansatz, the relation between the two metrics in this approach may be changed so as to bring out any desired FRW cosmology.