Chaotic new inflation and primordial spectrum of adiabatic fluctuations

In a number of scalar potentials with an unstable local maximum at the origin, chaotic inflation is followed by new inflation if model parameters of the potential are appropriately chosen. We calculate the spectrum of adiabatic fluctuations in such a double inflation model and show that it is possible to realize an almost scale-invariant spectrum with a sharp cutoff on a superhorizon scale, which may be favored observationally, and a tilted spectrum with the spectral index $n_{\mathrm{eff}}<0.95\mathrm{}$ on large scales.