Gravitational properties of light - The emission of counter-propagating laser pulses from an atom

TL;DR

This paper investigates the gravitational effects of laser pulses emitted by an atom, highlighting the entanglement between the pulse's gravitational field and the emitter's energy-momentum, and compares it to known metrics like Vaidya.

Contribution

It provides a detailed analysis of the gravitational field generated by counter-propagating laser pulses from an atom, revealing unique features of cause-effect propagation at light speed.

Findings

The gravitational field of emitted laser pulses is entangled with the emitter's energy-momentum.

The curvature effects on test particles depend on the emission process.

Comparison with Vaidya metric illustrates differences in radiation emission scenarios.

Abstract

The gravitational field of a laser pulse, although not detectable at the moment, comes with a peculiar feature which continues to attract attention; cause and effect propagate with the same speed, that of light. A particular result of this feature is that the gravitational field of an emitted laser pulse and the gravitational effect of the emitter's energy-momentum change are intimately entangled. In this article, a specific example of an emission process is considered - an atom, modeled as a point mass, emits two counter-propagating pulses. The corresponding curvature and the effect on massive and massless test particles is discussed. A comparison is made with the metric corresponding to a spherically symmetric massive object that isotropically emits radiation - the Vaidya metric.