Dynamical instability of the XY spiral state of ferromagnetic condensates

TL;DR

This paper investigates the stability of the XY spiral state in ferromagnetic condensates by analyzing collective excitations, revealing a dynamical instability at certain wavevectors, and mapping phase diagrams based on key parameters.

Contribution

It provides a detailed calculation of the excitation spectrum and identifies the conditions leading to dynamical instability in the XY spiral state of ferromagnetic condensates.

Findings

Spin wave excitation energies become imaginary beyond a critical wavevector.

Dynamical instability occurs at certain spiral wavevectors.

Phase diagrams are constructed as functions of wavevector and Zeeman energy.

Abstract

We calculate the spectrum of collective excitations of the XY spiral state prepared adiabatically or suddenly from a uniform ferromagnetic F=1 condensate. For spiral wavevectors past a critical value, spin wave excitation energies become imaginary indicating a dynamical instability. We construct phase diagrams as functions of spiral wavevector and quadratic Zeeman energy.