Formation and dynamics of many-boson fragmented states in attractive one-dimensional ultra-cold gases

TL;DR

This paper investigates the formation and behavior of many-boson fragmented states, called fragmentons, in attractive one-dimensional ultra-cold gases, revealing their stability, fragmentation, and delocalization through many-particle simulations.

Contribution

It introduces the concept of fragmentons as dynamically stable, two-fold fragmented states in attractive 1D bosonic gases, contrasting with mean-field predictions.

Findings

Fragmentons are two-fold fragmented and non-coherent.

They are dynamically stable and propagate without significant dispersion.

Their formation is explained by a static model predicting fragmented states.

Abstract

Dynamics of attractive ultra-cold bosonic clouds in one dimension are studied by solving the many-particle time-dependent Schr\"odinger equation. The initially coherent wave-packet can dynamically dissociate into two parts when its energy exceeds a threshold value. Noticeably, the time-dependent Gross-Pitaevskii theory applied to the same initial state does not show up the splitting. We call the split object {\it fragmenton}. It possesses remarkable properties: (1) it is two-fold fragmented, i.e., not coherent; (2) it is dynamically stable, i.e., it propagates almost without dispersion; (3) it is delocalized, i.e., the two dissociated parts still communicate with one another. A simple static model predicts the existence of fragmented states which are responsible for formation and dynamics of fragmentons.