RETRACTED: Perturbative analysis of multiple-field cosmological inflation

This article has been retracted at the request of the Authors. Please see http://www.elsevier.com/locate/withdrawalpolicy.Reason: The authors' statement, accepted by the Editors, is as follows: We recently [1] published a paper in Annals of Physics, which discussed at length the gauge independent analysis of cosmological perturbations of multiple fields using the ADM equations extended to first order in slow roll approximation. As is appropriate for a broadly-based journal such as this, we gave a pedagogical presentation of the method, based on earlier work by Hwang, Noh, Nibbelink and Van Tent (given as references [22], [25], [29], [30] in our article). However, we did not make sufficiently clear the extent to which our own contribution paralleled ones given in these earlier works. This seems to have given an impression that the results, that were already given in various parts of the literature cited in our reference and [22] in particular, were our own. In order to avoid misunderstanding on this point, we wish to withdraw the paper.