Revisiting wormhole energy conditions in Riemann-Cartan spacetimes and under Weyl transformations

Understand

We show that the violation of the null energy condition by matter, required by traversable wormholes, can be removed in spacetimes with torsion.

• In addition, we show that this violation can also be removed in the conformal frame obtained by a Weyl transformation.
• This comes about because both conformally transformed wormholes and wormholes in spacetimes with torsion become sustained thanks to a combination of 'normal' matter, that satisfies the null energy condition, and an induced 'geometric' energy-momentum tensor that is able to greatly violate the null energy condition.