Multi-field Conformal Cosmological Attractors
  We describe a broad class of multi-field inflationary models with
spontaneously broken conformal invariance. It generalizes the recently
discovered class of cosmological attractors with a single inflaton field. In
the new multi-field theories, just as in the previously studied single-field
models, the moduli space has a boundary (Kahler cone) in terms of the original
homogeneous conformal variables. Upon spontaneous breaking of the conformal
invariance and switching to the Einstein frame, this boundary moves to infinity
in terms of the canonically normalized inflaton field. This results in the
exponential stretching and flattening of scalar potentials in the vicinity of
the boundary of the moduli space, which makes even very steep potentials
perfectly suitable for the slow-roll inflation. These theories, just like their
single-field versions, typically lead to inflationary perturbations with n_s
=1-2/N and r = 12/N^2, where N is the number of e-foldings.
