Velocity Memory Effect for Polarized Gravitational Waves

TL;DR

This paper investigates the Velocity Memory Effect in polarized gravitational waves, analyzing particle trajectories and symmetries, revealing new behaviors and an additional isometry in circularly polarized waves.

Contribution

It uncovers the Velocity Memory Effect in polarized gravitational waves and explores the implications of an extra screw isometry in circularly polarized cases.

Findings

Test particles fly apart with constant velocity after the wave passes.

Trajectories inside the wave combine oscillatory and rotational motions.

Circularly polarized waves exhibit bounded or spiraling trajectories, with an additional symmetry.

Abstract

Circularly polarized gravitational sandwich waves exhibit, as do their linearly polarized counterparts, the Velocity Memory Effect: freely falling test particles in the flat after-zone fly apart along straight lines with constant velocity. In the inside zone their trajectories combine oscillatory and rotational motions in a complicated way. For circularly polarized periodic gravitational waves some trajectories remain bounded, while others spiral outward. These waves admit an additional "screw" isometry beyond the usual five. The consequences of this extra symmetry are explored.