Low-$\ell$ CMB from String-Scale SUSY Breaking?

Understand

Models of inflation are instructive playgrounds for supersymmetry breaking in Supergravity and String Theory.

• In particular, combinations of branes and orientifolds that are not mutually BPS can lead to \emph{brane supersymmetry breaking}, a phenomenon where non--linear realizations are accompanied, in tachyon--free vacua, by the emergence of steep exponential potentials.
• When combined with milder terms, these exponentials can lead to slow--roll after a fast ascent and a turning point.
• This leaves behind distinctive patterns of scalar perturbations, where pre--inflationary peaks can lie well apart from an almost scale invariant profile.