Anti-de-Sitter Island-Universes from 5D Standing Waves

Abstract

We construct simple standing wave solutions in a 5D space-time with a ghost scalar field. The nodes of these standing waves are 'islands' of 4D Minkowski space-time. For the 5D model with increasing (decreasing) warp factor there are a finite (infinite) number of nodes and thus Minkowski island-universes having different parameters, such as gravitational and cosmological constants. This feature is similar to the assumptions of the landscape models, which postulate a large number of universes with different parameters. This standing wave solution also provides a new localization mechanism - matter fields can reside only on Minkowski 'islands', where the background space-time does not oscillate.