Short Distance Physics and Initial State Effects on the CMB Power Spectrum

We investigate a modification in the action of inflaton due to noncommutativity leads to a nonstandard initial vacuum and oscillatory corrections in the initial power spectrum. We show that the presence of these oscillations causes a drop in the WMAP ${\chi }^2$ about $\Delta\chi^{2}\sim 8.5$. As a bonus, from the parameter estimation done in this work, we show that the noncommutative parameters can be precisely bound to ${10}^{16}$ GeV or ${10}^4$ GeV depending on the inflation scale.