Generation of perturbation after multi-field inflation

We explore a new possibility that some inflaton fields in multi-field inflation models satisfy the observed value of the spectral index so that the curvature perturbation generated by them through post-inflationary dynamics may be relevant for the current observations. We illustrate this point using a simple and reasonable multi-field chaotic inflation model motivated from string theory. Possible non-Gaussianity and the tensor-to-scalar ratio are briefly addressed. (c) 2007 Elsevier B.V. All rights reserved.