Bosons with attractive interactions in a trap: Is the ground state fragmented ?

TL;DR

This paper investigates whether a Bose-Einstein condensate with attractive interactions can become fragmented in a trap, using a simplified model, and finds that fragmentation is unlikely in metastable states.

Contribution

It introduces a two-level model to analyze condensate fragmentation with attractive interactions and discusses conditions for fragmentation in different trapping potentials.

Findings

Fragmentation does not occur in metastable states with negative scattering length.

The model suggests fragmentation is unlikely in typical harmonic traps.

Alternative trapping potentials may allow for condensate fragmentation.

Abstract

Possible fragmentation of a Bose-Einstein condensate with negative scattering length is investigated using a simple two-level model. Our results indicate that fragmentation does not take place for values of the coupling for which the system is metastable. We also comment on the possibility of realizing a fragmented condensate in trapping potentials other than an harmonic one.