Interface dynamics of a two-component Bose-Einstein condensate driven by an external force

TL;DR

This paper investigates the interface dynamics of a two-component Bose-Einstein condensate under various external forces, revealing different instability phenomena and the effects of stochastic forces on interface behavior.

Contribution

It derives the dispersion relation for interface waves and explores diverse dynamical effects, including instabilities and stabilization mechanisms, under different external force conditions.

Findings

Rayleigh-Taylor instability occurs under constant force

Richtmyer-Meshkov instability appears with pulse force

Non-Markovian stochastic forces cause exponential growth of perturbations

Abstract

The dynamics of an interface in a two-component Bose-Einstein condensate driven by a spatially uniform time-dependent force is studied. Starting from the Gross-Pitaevskii Lagrangian, the dispersion relation for linear waves and instabilities at the interface is derived by means of a variational approach. A number of diverse dynamical effects for different types of the driving force is demonstrated, which includes the Rayleigh-Taylor instability for a constant force, the Richtmyer-Meshkov instability for a pulse force, dynamic stabilization of the Rayleigh-Taylor instability and onset of the parametric instability for an oscillating force. Gaussian Markovian and non-Markovian stochastic forces are also considered. It is found that the Markovian stochastic force does not produce any average effect on the dynamics of the interface, while the non-Markovian force leads to exponential perturbation growth.