Bouncing universe and non-BPS branes

Understand

We describe string frame bouncing universe scenarios involving the creation and annihilation of a non-BPS D9-brane in type IIA superstring theory.

• We find several classes of solutions, in which the bounce is driven by the tachyon dynamics of the non-BPS brane.
• The metric and the dilaton are consistently described in terms of the lowest order effective action.
• The bounce solutions interpolate between contracting and expanding pre-big bang (or post-big bang) solutions.