# Nonlocal interactions in collapsing condensates in a box

## TL;DR

This paper explains the stability and observed plateaus in collapsing Bose-Einstein condensates in a box by modeling nonlocal attractive interactions, matching experimental data with a variational approach.

## Contribution

It introduces a nonlocal interaction model to explain stable remnant states and energy minima in collapsing condensates, providing a new theoretical framework.

## Key findings

- Remnant condensates correspond to two energy minima.
- Nonlocal interactions with a finite range explain experimental observations.
- The variational model accurately reproduces experimental data.

## Abstract

The collapse of attractive Bose-Einstein condensates in a box with tunable interatomic interactions was studied experimentally recently. Not only were remarkably stable remnant condensates observed, but furthermore they often seem to involve two stable plateaus. We suggest that these plateaus correspond in fact to two minima of the energy, the attractive atomic interactions being nonlocal. We show in detail that all the experimental data for these remnant condensates can be accounted for by minimising a variational energy involving a nonlocal interatomic potential that is attractive everywhere and that has a range of the order of the magnetic length.