Coupling vortex dynamics with collective excitations in Bose-Einstein condensates

Abstract

Here we analyze the collective excitations as well as the expansion of a trapped Bose-Einstein condensate with a vortex line at its center. To this end, we propose a variational method where the variational parameters have to be carefully chosen in order to produce reliable results. Our variational calculations agree with numerical simulations of the Gross-Pitaevskii equation. The system considered here turns out to exhibit four collective modes of which only three can be observed at a time depending of the trap anisotropy. We also demonstrate that these collective modes can be excited using well stablished experimental methods such as modulation of the s-wave scattering length.

Isothermal compressibility determination across Bose-Einstein condensation

“…In order to probe that the general results we found do not depend on the specific model for the analysis, we also tested an alternative, less constrained, model. We fitted our images with two Gaussians for the thermal and condensed components and we reconstructed the in situ profiles by applying a variational method [31][32][33] which has already proved to be valid to study the ballistic expansion dynamics of a condensate [32,33]. We checked that the Π(T ) curves, and therefore all the derived thermodynamic quantities, extracted with the two reconstructing methods are quantitatively comparable.…”

Collective excitation of Bose–Einstein condensate of 23Na via high-partial wave Feshbach resonance

“…Ultracold atomic gases are a powerful platform for providing a unique opportunity to investigate many interesting quantum phenomena in many-body physics [1], and especially study quantum matter in the presence of a variety of gauge fields [2,3], which give deep insights into physics that are difficult to realize in solid state systems [4][5][6][7][8][9]. Collective low energy excitation, which is a small deviation from static equilibrium, has been an essential probe tool for investigating properties of an atomic gas, for example collisional and dynamical properties [10][11][12][13][14][15][16][17][18][19][20][21], equation of state [22][23][24][25][26][27][28][29], and dynamical many-body physics in the mixture of bosonic and fermionic atoms [30][31][32][33][34].…”

Breathing mode in two-dimensional binary self-bound Bose gas droplets

“…Breathing mode oscillations were discussed in terms of the underlying symmetry properties of a Bose gas in two dimensions [53], and semiclassical methods have been probed to describe low-lying excitations in the limit of large boson numbers [54]. Collective excitations of BECs carrying vortices or vortex lattices have also been studied extensively; to mention only a few examples from the vast literature, see Refs [53][54][55][56][57][58][59][60][61][62]. More recently and in the context of Bose droplets, in Ref.…”