Three-forms can give rise to viable cosmological scenarios of inflation and dark energy with potentially observable signatures distinct from standard single scalar field models.

I will first present an intuitive picture of the background evolution of the minimally coupled three-form in terms of an effective potential and show that it can naturally generate a variety of isotropic background dynamics, including scaling, possibly transient acceleration and phantom crossing.

When applied to primordial inflation, a three-form can have a scale invariant scalar perturbations power spectrum and the consistency relation between the tensor and scalar amplitudes has a dependence on the speed of sound.  Finally, I will demonstrate that a single three-form can have large non-Gaussian signatures.

Place: Physics Dept. Meeting Room, 2th floor, IST