Power spectra in spacetime noncommutative inflation

The spacetime uncertainty relation, which deviates from general relativity, emerges in string/M-theory. It is possible to observe this deviation through cosmological experiments, in particular through the measurements of CMB power spectrum. This paper extends some previous observations to more general inflation schemes. We find that the noncommutative spacetime effects always suppress the power spectrum of both the scalar and tensor perturbations, and may provide a large enough running of the spectral index to fit the results of WMAP in the inflation model.