p-Wave stabilization of three-dimensional Bose-Fermi solitons

TL;DR

This paper demonstrates that p-wave interactions can stabilize three-dimensional Bose-Fermi solitons, preventing collapse and expanding the range of stable solutions in ultracold atomic mixtures.

Contribution

It introduces a variational model including s- and p-wave interactions, showing p-wave repulsion stabilizes solitons against collapse in Bose-Fermi gases.

Findings

p-wave interactions remove collapse instability

stability of solitons is enhanced by p-wave repulsion

stability range is widened for Bose-Fermi mixtures

Abstract

We explore bright soliton solutions of ultracold Bose-Fermi gases, showing that the presence of p-wave interactions can remove the usual collapse instability and support stable soliton solutions that are global energy minima. A variational model that incorporates the relevant s- and p-wave interactions in the system is established analytically and solved numerically to probe the dependencies of the solitons on key experimental parameters. Under attractive s-wave interactions, bright solitons exist only as meta-stable states susceptible to collapse. Remarkably, the presence of repulsive p-wave interactions alleviates this collapse instability. This dramatically widens the range of experimentally-achievable soliton solutions and indicates greatly enhanced robustness. While we focus specifically on the boson-fermion pairing of 87Rb and 40K, the stabilization inferred by repulsive p-wave interactions should apply to the wider remit of ultracold Bose-Fermi mixtures.