Finite-time future singularities in modified gravity

Understand

We review finite-time future singularities in modified gravity.

• We reconstruct an explicit model of modified gravity realizing a crossing of the phantom divide and show that the Big Rip singularity appears in the modified gravitational theory.
• It is also demonstrated that the (finite-time) Big Rip singularity in the modified gravity is transformed into the infinite-time singularity in the corresponding scalar field theory obtained through the conformal transformation.
• Furthermore, we study several models of modified gravity which produce accelerating cosmologies ending at the finite-time future singularities of all four known types.