Controlling dark solitons on the healing length scale

TL;DR

This paper demonstrates that impurity atoms trapped in a dark soliton within a Bose-Einstein condensate can be used to precisely control the soliton's position, velocity, and interactions, surpassing traditional optical resolution limits.

Contribution

It introduces a novel method of controlling dark solitons via impurity atoms, enabling manipulation at scales below the optical diffraction limit.

Findings

Impurity atoms can fully control dark soliton dynamics.

Controlled collisions between solitons are achievable.

Sub-diffraction control of matter waves is demonstrated.

Abstract

While usually the optical diffraction limit is setting a limit for the lengthscales on which a typical alkali Bose-Einstein condensate can be controlled, we show that in certain situations control via matter waves can achieve smaller resolutions. For this we consider a small number of impurity atoms which are trapped inside the density dip of a dark soliton state and show that any grey soliton can be obtained by just driving the impurity atoms. By controlling the driving force on the impurity, one can therefore fully control the position and velocity of the dark soliton, and also study controlled collisions between these non-linear objects.