Vortex properties in the extended supersolid phase of dipolar Bose-Einstein condensates

Francesco Ancilotto, Manuel Barranco, Martí Pi, Luciano Reatto
2021 Physical Review A  
We study the properties of singly quantized linear vortices in the supersolid phase of a dipolar Bose-Einstein condensate at zero-temperature modeling 164 Dy atoms. The system is extended in the x-y plane and confined by a harmonic trap in the polarization direction z. Our study is based on a generalized Gross-Pitaevskii equation. We characterize the ground state of the system in terms of spatial order and superfluid fraction and compare the properties of a single vortex and of a vortex dipole
more » ... n the superfluid phase (SFP) and in the supersolid phase (SSP). At variance with a vortex in the SFP, which is free to move in the superfluid, a vortex in the SSP is localized at the interstitial sites and does not move freely. We have computed the energy barrier for motion from an equilibrium site to another. The fact that the vortex is submitted to a periodic potential has a dramatic effect on the dynamics of a vortex dipole made of two counter-rotating parallel vortices; instead of rigidly translating as in the SFP, the vortex and antivortex approach each other by a series of jumps from one site to another until they annihilate in a very short time and their energy is transferred to bulk excitations.
doi:10.1103/physreva.103.033314 fatcat:gtcfooilmjhatjh35iv35vocgu