Some remarks on oscillating inflation - art. no. 027302

In a recent paper Damour and Mukhanov described a scenario where inflation may continue during the oscillatory phase. This effect is possible because the scalar field spends a significant fraction of each period of oscillatio n on the upper part of the potential. Such an additional period of inflatio n could push perturbations after the slow roll regime to observable scales. Although in this work we show that the small region of the Damour-Mukhanov parameter q gives the main contribution to oscillating inflation, it was n ot satisfactorily understood until now. Furthermore, it gives an expression for the energy density spectrum of perturbations, which is well behaved in the whole physical range of q.