Fission of multielectron bubbles in liquid helium

TL;DR

This paper investigates the stability and fission behavior of multielectron bubbles in liquid helium, revealing conditions for metastability and the existence of energy barriers that prevent fissioning under certain pressures.

Contribution

It introduces a liquid-drop model approach to analyze MEB stability, overcoming previous limitations of the Rayleigh-Plesset equation and providing new insights into bubble geometry limits.

Findings

Positive pressure can induce fission instability.

Negative pressure stabilizes small deformations.

Energy barrier causes metastability at zero pressure.

Abstract

The stability of multielectron bubbles (MEBs) in liquid helium is investigated using the liquid-drop model for fissioning nuclei. Whereas a critical positive pressure can make the bubble unstable against fissioning, a small negative pressure suffices to introduce a restoring force preventing any small deformation of the bubble to grow. We also find that there exists an energy barrier making MEBs metastable against fissioning at zero pressure. The results obtained here overcome the difficulties associated with the Rayleigh-Plesset equation previously used to study bubble stability, and shed new light on the limits of achievable bubble geometries in recently proposed experiments devised to stabilize MEBs.