Rotating saddle trap as Foucault's pendulum

TL;DR

This paper explains the precessional motion observed in a particle within a rotating saddle potential as a Coriolis-like force, providing a novel example of such a force in an inertial frame and proposing a mechanical demonstration.

Contribution

It introduces the first example of a Coriolis-like force in an inertial frame caused by a rotating saddle potential and suggests a simple mechanical demonstration.

Findings

Precessional motion is due to a Coriolis-like force.

First example of such force in an inertial frame.

Proposes a mechanical demonstration of the effect.

Abstract

One of the many surprising results found in the mechanics of rotating systems is the stabilization of a particle in a rapidly rotating planar saddle potential. Besides the counterintuitive stabilization, an unexpected precessional motion is observed. In this note we show that this precession is due to a Coriolis-like force caused by the rotation of the potential. To our knowledge this is the first example where such force arises in an inertial reference frame. We also propose an idea of a simple mechanical demonstration of this effect.