Scalar dark energy models mimicking $\Lambda$CDM with arbitrary future evolution

Understand

Dark energy models with various scenarios of evolution are considered from the viewpoint of the formalism for the equation of state.

• It is shown that these models are compatible with current astronomical data.
• Some of the models presented here evolve arbitrarily close to $\Lambda$CDM up to the present, but diverge in the future into a number of different possible asymptotic states, including asymptotic de-Sitter (pseudo-rip) evolution, little rips with disintegration of bound structures, and various forms of finite-time future singularities.
• Therefore it is impossible from observational data to determine whether the universe will end in a future singularity or not.