Cosmic microwave background anisotropies with mixed isocurvature perturbations - art. no. 231301

In the light of the recent high quality data of the cosmic microwave backgr ound anisotropies, several estimations of cosmological parameters have been published. We study to what extent these estimations depend on assumptions about the initial conditions of the cosmological perturbations, which are usually supposed to be adiabatic. We show that, for more generic initial co nditions, not only the best fit values are very different but the allowed p arameter range enlarges dramatically. This raises the question which cosmol ogical information (matter content of the Universe vs physics of inflation) can be reliably extracted from these data.