Gravitational orbital Hall effect of vortex light in Lense-Thirring metric

TL;DR

This paper investigates how vortex light with intrinsic orbital angular momentum behaves in a gravitational field, revealing deviations from null geodesics that differ from spin-based effects, thus uncovering a new gravitational interaction.

Contribution

It models vortex light as Laguerre-Gaussian waves in the Lense-Thirring metric and analyzes its unique gravitational orbital Hall effect, highlighting differences from spin-based gravitational phenomena.

Findings

Vortex light trajectories deviate from null geodesics both perpendicular and within the geodesic plane.

Deviation depends differently on orbital angular momentum than on spin.

The gravitational orbital Hall effect of vortex light is distinct from the spin Hall effect, indicating a new gravity interaction.

Abstract

Vortex light, characterized by an intrinsic orbital angular momentum aligned with its propagation direction, is described through vortex electromagnetic waves. Similar to the gravitational spin Hall effect (SHE), vortex light is expected to exhibit intrinsic orbital angular momentum dependent trajectories and deviations from the null geodesic plane when propagating through a gravitational field, a phenomenon termed the gravitational orbital Hall effect (OHE). In this work, we model the vortex light as vortex Laguerre-Gaussian electromagnetic wave packets and analyze its motion by solving covariant Maxwell equations within the Lense-Thirring metric. Our findings reveal that the trajectory of vortex light with an intrinsic orbital angular momentum deviates from the null geodesic in two ways. It deviates both perpendicular to, and within, the null geodesic plane. This behavior contrasts with the gravitational SHE, where spin-polarized light primarily deviates perpendicular to the null geodesic plane. Moreover, the relationship between the deviation and intrinsic orbital angular momentum differs significantly from that between the deviation and spin. These results suggest a unique interaction between intrinsic orbital angular momentum and gravity, distinct from the spin-gravity coupling, indicating that the gravitational OHE of light might not be precisely predicted by merely substituting spin with intrinsic orbital angular momentum in the gravitational SHE of light.