Evolution of Perturbations in a Noncommutative Braneworld Inflation

Abstract

Following our previous work in noncommutative braneworld inflation (arXiv:0911.4418), in this paper we use the smeared, coherent state picture of noncommutativity to study evolution of perturbations in a noncommutative braneworld scenario. We show that in this setup, the early stage of the universe evolution has a phantom evolution with imaginary effective sound speed. We show also that the amplitude of perturbations in the commutative regime decays faster than the noncommutative regime with the same parameter values, and as a result we need smaller number of e-folds in the noncommutative regime to have a successful braneworld inflation.