The null energy condition in dynamic wormholes

TL;DR

This paper proves that violations of the null energy condition are unavoidable in dynamic wormholes, extending previous results to non-symmetric, time-dependent cases using local geometric analysis.

Contribution

It generalizes the null energy condition violation proof to non-symmetric, time-dependent wormholes without relying on global assumptions, focusing on local geometric properties.

Findings

Time-dependent wormholes have two throats, one for each direction.

The two throats coalesce only in static wormholes.

Violations of the null energy condition are universal in traversable wormholes.

Abstract

We extend previous proofs that violations of the null energy condition (NEC) are a generic and universal feature of traversable wormholes to completely non-symmetric time-dependent wormholes. We show that the analysis can be phrased purely in terms of local geometry at and near the wormhole throat, and do not have to make any technical assumptions about asymptotic flatness or other global properties. A key aspect of the analysis is the demonstration that time-dependent wormholes have two throats, one for each direction through the wormhole, and that the two throats coalesce only for the case of a static wormhole.