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

## TL;DR

This paper demonstrates that in Riemann-Cartan spacetimes with torsion and under Weyl transformations, the need for matter to violate the null energy condition in traversable wormholes can be eliminated, thanks to geometric contributions.

## Contribution

It shows that wormholes can be supported without violating energy conditions by matter, through geometric effects in torsionful spacetimes and conformal frames.

## Key findings

- Null energy condition violation can be removed in torsionful spacetimes.
- Weyl transformations can eliminate the need for exotic matter.
- Geometric energy-momentum tensors support wormholes without violating energy conditions.

## Abstract

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.