Supersymmetric vacuum configurations in string cosmology

We examine in a cosmological context the conditions for unbroken supersymmetry in $N=1\mathrm{}$ supergravity in $D=10\mathrm{}$ dimensions. We show that the cosmological solutions of the equations of motion obtained considering only the bosonic sector correspond to vacuum states with spontaneous supersymmetry breaking. With a nonvanishing gravitino-dilatino condensate we find a solution of the equations of motion that satisfies necessary conditions for unbroken supersymmetry and that smoothly interpolates between Minkowski space and de Sitter space with a linearly growing dilaton, thus providing a possible example of a supersymmetric and nonsingular pre-big-bang cosmology.