Phase-space analysis of teleparallel dark energy

We perform a detailed dynamical analysis of the teleparallel dark energy scenario, which is based on the teleparallel equivalent of General Relativity, in which one adds a canonical scalar field, allowing also for a nonminimal coupling with gravity. We find that the universe can result in the quintessence-like, dark-energy-dominated solution, or to the stiff dark-energy late-time attractor, similarly to standard quintessence. However, teleparallel dark energy possesses an additional late-time solution, in which dark energy behaves like a cosmological constant, independently of the specific values of the model parameters. Finally, during the evolution the dark energy equation-of-state parameter can be either above or below -1, offering a good description for its observed dynamical behavior and its stabilization close to the cosmological-constant value. © 2012 IOP Publishing Ltd and Sissa Medialab srl.