We study nonperturbative moduli superpotentials with positive exponents, i.e. the form like $A{e}^{aT}$ with a positive constant $a$ and the modulus $T$. These effects can be generated, e.g., by D-branes which have negative Ramond-Ramond charge of the lower-dimensional D-brane. The scalar potentials including such terms have quite a rich structure. There are several local minima with different potential energies and a high barrier, whose height is of $\mathcal{O}(M_p^4)$. We discuss their implications from the viewpoints of cosmology and particle phenomenology, e.g. the realization of inflation models, avoiding the overshooting problem. This type of potential would be useful to realize the inflation and low-energy supersymmetry breaking.

• Received 13 May 2008

DOI:https://doi.org/10.1103/PhysRevD.78.025007