Static-response theory and the roton-maxon spectrum of a flattened dipolar Bose-Einstein condensate

Abstract

Important information for the roton-maxon spectrum of a flattened dipolar Bose-Einstein condensate is extracted by applying a static perturbation exhibiting a periodic in-plane modulation. By solving the Gross-Pitaevskii equation in the presence of the weak perturbation we evaluate the linear density response of the system and use it, together with sum rules, to provide a Feynman-like upperbound prediction for the excitation spectrum, finding excellent agreement with the predictions of full Bogoliubov calculations. By suddenly removing the static perturbation, while still maintaining the trap, we find that the density modulations -as well as the weights of the perturbation-induced side peaks of the momentum distribution -undergo an oscillatory behavior with double the characteristic frequency of the excitation spectrum. The measurement of the oscillation periods could provide an easy determination of dispersion relations. arXiv:1901.04875v2 [cond-mat.quant-gas]

Topological defects in rotating spin–orbit-coupled dipolar spin-1 Bose–Einstein condensates

“…On the other hand, quantum gases with magnetic dipole-dipole interaction (DDI), especially the BECs with DDI, have also drawn much attention both experimentally [35][36][37][38] and theoretically [39][40][41][42][43][44][45][46][47][48] in recent years. Relevant studies on spinor BECs with DDI have shown that the interplay between the short-range spin-exchange interaction and the long-range anisotropic DDI can lead to rich topological defects, spin textures and spin dynamics [39,40].…”

Topological defects in rotating spin-orbit-coupled dipolar spin-1 Bose-Einstein condensates

“…On the other hand, quantum gases with magnetic dipole-dipole interaction (DDI), especially the BECs with DDI, have also drawn much attention both experimentally [35][36][37][38] and theoretically [39][40][41][42][43][44][45][46][47][48] in recent years. Relevant studies on spinor BECs with DDI have shown that the interplay between the short-range spin-exchange interaction and the long-range anisotropic DDI can lead to rich topological defects, spin textures and spin dynamics [39,40].…”