Phase fluctuations in a confined fluid

TL;DR

This paper investigates phase fluctuations in confined fluids, focusing on bubble stability, metastability, and phase flipping phenomena, supported by theoretical analysis and Lennard-Jones fluid simulations.

Contribution

It introduces a study of bubble lifetime and phase flipping in small confined systems, highlighting the conditions for metastability and dynamic phase transitions.

Findings

Metastable bubbles have finite lifetimes depending on system size.

Phase flipping observed in Lennard-Jones fluid simulations.

Small systems can exhibit oscillations between different fluid phases.

Abstract

Fluid phase equilibrium depends on the external constraints imposed on a system. In a closed system with fixed volume, depending on the average density, a vapor bubble may be stable, metastable, or unstable, with respect to the homogeneous liquid phase. In the case where the bubble is metastable, we study its lifetime, i.e. the average waiting time needed to observe bubble collapse, and the corresponding lifetime of the homogeneous liquid. For the smallest systems, we predict the possibility to observe phase flipping, when the fluid oscillates between states with and without bubble. We provide an example of phase flipping in a simulation of a Lennard-Jones fluid.