Phase Structure of Bose - Einstein Condensate in Ultra - Cold Bose Gases

Solitons for nearly integrable bright spinor Bose-Einstein condensate

‎Using the explicit forms of eigenstates for linearized operator related to a matrix version of Nonlinear Schrödinger equation‎, ‎soliton perturbation theory is developed for the $F=1$ bright spinor Bose-Einstein condensates‎. ‎A small disturbance of the integrability condition can be considered as a small correction to the integrable equation‎. ‎By choosing appropriate perturbation‎, ‎the soli...

Fluctuations of Bose-Einstein Condensate

The recent achievement of Bose-Einstein condensation (BEC) in trapped atoms of dilute gases [1–3] has been quickly followed by the quantitative measurements of the condensate’s properties. In particular the dependence of the fraction of atoms in the condensate on the temperature has been found to be in agreement with the theory of the noninteracting Bose gas in a harmonic trap [4]. From the poi...

Ultracold Bose Gases in 1D Disorder: From Lifshits Glass to Bose-Einstein Condensate

Stirring a Bose–Einstein condensate

By shining a tightly focused laser light on a Bose–Einstein condensate (BEC) and moving the centre of the beam along a spiral path one may stir the BEC and create vortices. It is shown that one can induce rotation of the BEC in the direction opposite to the direction of stirring. When a spoon, stick or another object of a similar shape is used to stir a liquid, the liquid rotates in the directi...

Quantum phase transition in an antiferromagnetic spinor Bose-Einstein condensate.

We have experimentally observed the dynamics of an antiferromagnetic sodium Bose-Einstein condensate quenched through a quantum phase transition. Using an off-resonant microwave field coupling the F = 1 and F = 2 atomic hyperfine levels, we rapidly switched the quadratic energy shift q from positive to negative values. At q = 0, the system undergoes a transition from a polar to antiferromagneti...