Bose gas with two- and three-particle interaction: evolution of soliton-like bubbles

Vladmir G. Makhankov, Kholmirzo T. Kholmurodov

The problem of Bose-condensate stability is studied in the model with two-particle attraction and three-particle repulsion. Two channels of condensate decomposition are established, one of which is associated with an excitation of one bubble and the other with bubble gas in the condensate. Calculations show that the gas channel of decomposition is more advantageous from the energy point of view since it takes place at lower temperatures in comparison with the one-soliton channel.

Li, Sheng-Chang, Duan Duan +1 more

Yan Li, Yan-Hong Qin, Li-Chen Zhao +2 more

Abstract We investigate kink-dark complex solitons (KDCSs) in a three-component Bose–Einstein condensate (BEC) with repulsive interactions and pair-transition (PT) effects. Soliton profiles critically depend on the phase differences between dark solitons excitation elements. We report a type of kink-dark soliton profile which shows a droplet-bubble-droplet with a density dip, in sharp contrast to previously studied bubble-droplets. The interaction between two KDCSs is further investigated. It demonstrates some striking particle transition behaviours during their collision processes, while soliton profiles survive after the collision. Additionally, we exhibit the state transition dynamics between a kink soliton and a dark soliton. These results suggest that PT effects can induce more abundant complex solitons dynamics in multi-component BEC.

Deke Li, Dun Zhao

Alexandre Heuchamps

Pascal Naidon

Mixing two kinds of particles that repel each other usually results in either a homogeneous mixture when the repulsion is weak, or a complete phase separation of the two kinds when their repulsion is too strong. It is shown however that there is an intermediate regime where the two kinds can coexist in their ground state as a bubble immersed in a gas of one kind. Such a situation is obtained by adding heavy repulsive impurities into a Bose-Einstein condensate. Above a certain strength of the mutual repulsion, a stable bubble of impurities and bosons can be formed, resulting from the equilibrium between the interactions induced by the bosons inside the bubble and the outside pressure from the surrounding bosons. At some particular strength, the effective interactions between the impurities consist of only three-body interactions. Finally, above a critical strength, the bosons are ejected from the bubble and the impurities collapse into a pure bubble of impurities. This phenomenon could be observed with an imbalanced mixture of ultra-cold atoms of different masses. Moreover, it appears possible to reach a regime where the impurities form a dense bubble of strongly-interacting particles.