# Spin mixing and protection of ferromagnetism in a spinor dipolar condensate

## TL;DR

This paper investigates spin mixing in a chromium dipolar Bose-Einstein Condensate, revealing how dipolar and contact interactions influence ferromagnetic stability and dynamics under various conditions.

## Contribution

It demonstrates the role of contact interactions and external magnetic gradients in controlling spin mixing and ferromagnetic protection in dipolar condensates.

## Key findings

- Spin mixing is primarily driven by dipolar coupling.
- Contact interactions help preserve ferromagnetism during dynamics.
- External magnetic gradients enable spin dynamics at specific angles.

## Abstract

We study spin mixing dynamics in a chromium dipolar Bose-Einstein Condensate, after tilting the atomic spins by an angle $\theta$ with respect to the magnetic field. Spin mixing is triggered by dipolar coupling, but, once dynamics has started, it is mostly driven by contact interactions. For the particular case $\theta=\pi/2$, an external spin-orbit coupling term induced by a magnetic gradient is required to enable the dynamics. Then the initial ferromagnetic character of the gas is locally preserved, an unexpected feature that we attribute to large spin-dependent contact interactions.