Lightlike Branes as Natural Candidates for Wormhole Throats

TL;DR

This paper develops a consistent description of lightlike branes, showing they naturally occupy horizons and can produce traversable wormholes with parameters determined by their dynamical tension.

Contribution

It introduces a dual Lagrangian formulation of lightlike branes and demonstrates their role in forming traversable wormholes in Einstein-Maxwell systems.

Findings

Lightlike branes automatically occupy horizons in symmetric backgrounds.

LL-branes can produce traversable wormholes with tension-dependent parameters.

The tension of LL-branes is a dynamical degree of freedom.

Abstract

We first briefly present a consistent world-volume Lagrangian description of lightlike p-branes (LL-branes) in two equivalent forms - a Polyakov-type and a dual to it Nambu-Goto-type formulations. The most important characteristic features of LL-brane dynamics are: (i) the brane tension appears as a non-trivial additional dynamical degree of freedom; (ii) consistency of LL-brane dynamics in a spherically or axially symmetric gravitational background of codimension one requires the presence of an event horizon which is automatically occupied by the LL-brane ("horizon straddling"). Next we consider a bulk Einstein-Maxwell system interacting self-consistently with a codimension one LL-brane. We find spherically symmetric traversable wormhole solutions of Misner-Wheeler type produced by the LL-brane sitting at the wormhole throat with wormhole parameters being functions of the dynamical LL-brane tension.