Evidence for an oscillating soliton/vortex ring by density engineering of a Bose–Einstein condensate

Abstract

Two intriguing shapes that appear in Bose–Einstein condensates are vortex rings and solitons. Experiments now suggest that there can be periodic oscillations between these qualitatively different structures. When two Bose–Einstein condensates collide with high collisional energy, the celebrated matter-wave interference pattern appears1. For lower collisional energies, the repulsive interaction energy becomes significant, and the interference pattern evolves into an array of grey solitons2,3. But the lowest collisional energies, producing a single pair of solitons, have not been probed so far. Here, we report on experiments using density engineering on the healing length scale3,4 to produce such a pair of solitons. We see evidence that the solitons evolve periodically between vortex rings and solitons. The stable, periodic evolution is in sharp contrast to the behaviour seen in previous experiments5,6 in which the solitons decay irreversibly into vortex rings through the so-called snake instability7,8,9,10,11,12,13. The evolution can be understood in terms of conservation of mass and energy in a narrow condensate.

Cite this article

Shomroni, I., Lahoud, E., Levy, S. et al. Evidence for an oscillating soliton/vortex ring by density engineering of a Bose–Einstein condensate. Nature Phys 5, 193–197 (2009). https://doi.org/10.1038/nphys1177

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