The Smeared Null Energy Condition

TL;DR

This paper introduces a new bound on the average null energy in quantum field theories coupled to gravity, suggesting negative energy regions are limited and cannot be strongly gravitating or isolated.

Contribution

It proposes a novel bound on the average null energy along finite null geodesics, applicable at small scales in quantum field theories with gravity.

Findings

Negative energy regions are constrained by the bound.

Isolated negative energy regions are forbidden.

Negative energy cannot be strongly gravitating.

Abstract

We propose a new bound on the average null energy along a finite portion of a null geodesic. We believe our bound is valid on scales small compared to the radius of curvature in any quantum field theory that is consistently coupled to gravity. If correct, our bound implies that regions of negative energy density are never strongly gravitating, and that isolated regions of negative energy are forbidden.