N-flation from multiple DBI type actions

Abstract

In this letter we present a new N-flation model constructed by making use of multiple scalar fields which are being described by their own DBI action. We show that the dependence of the e-folding number and of the curvature perturbation on the number of fields changes compared with the normal N-flation model. Our model is also quite different from the usual DBI N-flation which is still based on one DBI action but involves many moduli components. Some specific examples of our model have been analyzed.

Figures (1)

• Figure 1: $n_s$ as the function of the e-folding number ${\cal N}$ for different values of the variable $x$($\equiv N\cdot\Delta/\phi_0$). The black solid line denotes the spectral index in the first case when all the scalars have the same value at horizon-crossing; the red dashed line denotes the spectral index in the second case with $x=10$; the orange dotted line $x=50$; the blue dash-dotted line $x=100$.