Induced-gravity inflation

Abstract

The possibility of inflation during induced-gravity spontaneous symmetry breaking with Zee's Lagrangian $\mathcal{L}=\frac{\ensuremath{\xi}{\ensuremath{\varphi}}^{2}R}{2}+\frac{{\ensuremath{\partial}}_{i}\ensuremath{\varphi}{\ensuremath{\partial}}^{i}\ensuremath{\varphi}}{2}\ensuremath{-}\frac{{\ensuremath{\lambda}({\ensuremath{\varphi}}^{2}\ensuremath{-}{\ensuremath{\nu}}^{2})}^{2}}{8}$ is confirmed. The "ordinary" and "chaotic" versions of this model are compared and found to differ substantially regarding the constraints on initial conditions and field parameters. The "chaotic" model proves to be more attractive in most respects. In particular, the previous belief that $\ensuremath{\lambda}$ has to be excessively small is shown to be founded only for "ordinary" inflation.