Repeated crossing of two concentric spherical thin-shells with charge

TL;DR

This paper demonstrates that by adding precisely tuned electric charges to two concentric spherical thin-shells in general relativity, their collapse can be indefinitely delayed, resulting in perpetual oscillatory motion.

Contribution

It introduces a novel mechanism using finely tuned electric charges to achieve perpetual two-body motion in a relativistic setting.

Findings

Electric charges delay shell collapse indefinitely

Perpetual oscillatory motion achieved with fine-tuned charges

Provides a new example of stable two-body dynamics in GR

Abstract

Interaction / collision of two concentric spherical thin-shells of linear fluid resulting in collapse has been considered recently. We show that addition of finely tuned electric charges on the shells apart from the cosmological constant serves to delay the collapse indefinitely, yielding an ever colliding system of two concentric fluid shells. Given the finely tuned charges this provides an example of a perpetual two-body motion in general relativity.