Positivity of the Bondi Energy in Einstein-Maxwell Axion- Dilaton Gravity

TL;DR

This paper proves the positivity of Bondi energy in Einstein-Maxwell axion-dilaton gravity, a low-energy string theory limit, extending the proof to hypersurfaces with inner boundaries.

Contribution

It provides the first proof of Bondi energy positivity in this specific gravity theory, including cases with inner boundaries.

Findings

Bondi energy positivity established for Einstein-Maxwell axion-dilaton gravity.

Generalization of the proof to hypersurfaces with inner boundaries.

Reinforces the physical viability of the theory through energy positivity.

Abstract

We present a proof of the positivity of the Bondi energy in Einstein-Maxwell axion-dilaton gravity, being the low-energy limit of the heterotic string theory. We consider the spacelike hypersurface which asymptotically approaches a null cone and on which the equations of the theory under consideration are given. Next, we generalize the proof allowing the hypersurface having inner boundaries.