A Galileon design of slow expansion: Emergent universe

We parameterize the evolutions of the slow expansion, which emerges from a static state in infinite past, into different classes. We show that the scale invariant adiabatical perturbation may be generated during these evolutions, and the corresponding evolutions can be realized with generalized Galileon Lagrangians, in which there is not the ghost instability. (c) 2012 Published by Elsevier B.V.