Wormholes in String Theory

TL;DR

This paper demonstrates the theoretical construction of wormholes within string theory frameworks, showing they can be supported by matter satisfying standard energy conditions, thus potentially avoiding exotic matter.

Contribution

It introduces a method to construct wormholes in string theory that are supported by normal matter, challenging the notion that exotic matter is always required.

Findings

Wormholes can be constructed with matter satisfying weak and dominant energy conditions.

Dilaton fields can violate energy conditions and support wormholes.

Charged dilaton wormholes with generalized coupling are also feasible.

Abstract

A wormhole is constructed by cutting and joining two spacetimes satisfying the low energy string equations with a dilaton field. In spacetimes described by the "string metric" the dilaton energy-momentum tensor need not satisfy the weak or dominant energy conditions. In the cases considered here the dilaton field violates these energy conditions and is the source of the exotic matter required to maintain the wormhole. There is also a surface stress-energy, that must be produced by additional matter, where the spacetimes are joined. It is shown that wormholes can be constructed for which this additional matter satisfies the weak and dominant energy conditions, so that it could be a form of "normal" matter. Charged dilaton wormholes with a coupling between the dilaton and the electromagnetic field that is more general than in string theory are also briefly discussed.