Space-Time Compactification/Decompactification Transitions Via Lightlike Branes

Understand

We consider Einstein-Maxwell-Kalb-Ramond gravity-matter system in bulk space-time interacting self-consistently with two (widely separated) codimension-one electrically charged lightlike branes.

• The lightlike brane dynamics is explicitly given by manifestly reparametrization invariant world-volume actions in two equivalent dual to each other formulations (Polyakov-type and Nambu-Goto-type ones) proposed in our previous work.
• We find an explicit solution of the pertinent Einstein-Maxwell-Kalb-Ramond-lightlike-brane equations of motion describing a "two-throat" wormhole-like space-time consisting of a "left" compactified Bertotti-Robinson universe connected to a "middle" non-compact Reissner-Nordstroem-de-Sitter space-time region, which in turn is connected to another "right" compactified Bertotti-Robinson universe.
• Each of the lightlike branes automatically occupies one of the "throats", so that they dynamically induce a sequence of spontaneous space-time compactification/decompactification transitions.