A stringy realization of a small and positive cosmological constant in dark bubble cosmology

Understand

In this paper we construct a stringy embedding of the dark bubble model of an expanding 4D cosmology with the help of branes rotating in extra dimensions.

• The universe rides a bubble which has nucleated in an unstable higher dimensional background.
• Our construction is therefore a string theoretical realization of Vilenkin's quantum cosmology.
• While the cosmological constant vanishes at lowest order, loop corrections predicted by the Weak Gravity Conjecture can induce a phenomenologically viable value.