Quantum Vortex in a Vectorial Bose-Einstein Condensate

Quantum vortices in the multi-component Bose-Einstein condensation (BEC) are investigated theoretically. It is found that three kinds of the vortex configurations are possible and their physical properties are discussed in details, including the density distribution and the spin texture. By using the Bogoliubov theory extended to the three component BEC, the collective modes for these vortices are evaluated. The local vortex stability for these vortices are examined in light of the existence of the negative eigenvalue, yielding a narrow magnetization window for the local intrinsic stable region where the multi-components work together to stabilize a vortex in a self-organized way.Comment: 8 pages, 14 eps figure

Vortex phase diagram in trapped Bose-Einstein condensation

The vortex phase diagram in the external rotation frequency versus temperature is calculated for dilute Bose-Einstein condensed gases. It is determined within the Bogoliubov-Popov theory for a finite temperature where the condensate and non-condensate fractions are treated in an equal footing. The temperature dependences of various thermodynamic instability lines for the vortex nucleation are computed to construct the phase diagram. Experiments are proposed to resolve a recent controversy on the vortex creation problem associated with the quantized vortex observation in $^{87}$Rb atom gases.Comment: 11 pages, 8 figure

Infinitely many standard trisection diagrams for Gluck twisting

Gay and Meier asked if a trisection diagram for the Gluck twist on a spun or twist-spun 2-knot in $S^4$ obtained by a certain method is standard. In this paper, we show that the trisection diagram for the Gluck twist on the spun $(p+1,-p)$-torus knot is standard, where $p$ is any integer greater than or equal to 2.Comment: 16 pages, 17 figure

A simple method to create a vortex in Bose-Einstein condensate of alkali atoms

Bose-Einstein condensation in alkali atoms has materialized quite an interesting system, namely a condensate with a spin degree of freedom. In analogy with the A-phase of the superfluid $^3$He, numerous textures with nonvanishing vorticity have been proposed. In the present paper, interesting properties of such spin textures are analyzed. We propose a remarkably simple method to create a vortex state of a BEC in alkali atoms.Comment: 2 pages, 1 eps figure. Proceedings of LT22. The title is changed from the submitted version: Vortices in Bose-Einstein condensate with spin degree of freedo

On the effect of the thermal gas component to the stability of vortices in trapped Bose-Einstein condensates

We study the stability of vortices in trapped single-component Bose-Einstein condensates within self-consistent mean-field theories--especially we consider the Hartree-Fock-Bogoliubov-Popov theory and its recently proposed gapless extensions. It is shown that for sufficiently repulsively interacting systems the anomalous negative-energy modes related to vortex instabilities are lifted to positive energies due to partial filling of the vortex core with noncondensed gas. Such a behavior implies that within these theories the vortex states are eventually stable against transfer of condensate matter to the anomalous core modes. This self-stabilization of vortices, shown to occur under very general circumstances, is contrasted to the predictions of the non-self-consistent Bogoliubov approximation, which is known to exhibit anomalous modes for all vortex configurations and thus implying instability of these states. In addition, the shortcomings of these approximations in describing the properties of vortices are analysed, and the need of a self-consistent theory taking properly into account the coupled dynamics of the condensate and the noncondensate atoms is emphasized.Comment: 8 page

Precessional motion of a vortex in a finite-temperature Bose-Einstein condensate

We study the precessing motion of a vortex in a Bose-Einstein condensate of atomic gases. In addition to the former zero-temperature studies, finite temperature systems are treated within the Popov and semiclassical approximations. Precessing vortices are discussed utilizing the rotating frame of reference. The relationship between the sign of the lowest excitation energy and the direction of precession is discussed in detail.Comment: 6 pages, 9 figures. More discussion in Sec.III. Reference is update