Elementary excitations in dipolar spin-1 Bose-Einstein condensates

TL;DR

This paper numerically investigates the low-energy excitation spectra of dipolar spin-1 Bose-Einstein condensates, revealing how dipolar interactions influence spin wave and quadrupole mode energies in various spin textures.

Contribution

It provides a detailed numerical analysis of excitation spectra in dipolar spin-1 BECs, including effects of dipolar interactions on different spin textures and modes.

Findings

Dipolar interactions increase energies of spin waves and quadrupole modes.

Density oscillation energies are minimally affected by dipolar interactions.

Different spin textures exhibit distinct excitation spectrum behaviors.

Abstract

We have numerically solved the low-energy excitation spectra of ferromagnetic Bose-Einstein condensates subject to dipolar interparticle interactions. The system is assumed to be harmonically confined by purely optical means, thereby maintaining the spin degree of freedom of the condensate order parameter. Using a zero-temperature spin-1 model, we solve the Bogoliubov excitations for different spin textures, including a spin-vortex state in the absence of external magnetic fields and a rapidly rotating polarized spin texture in a finite homogeneous field. In particular, we consider the effect of dipolar interactions on excitations characteristic of ferromagnetic condensates. The energies of spin waves and magnetic quadrupole modes are found to increase rapidly with the dipolar coupling strength, whereas the energies of density oscillations change only slightly.