Multi-component Bose gases as a platform for controllably creating Peregrine solitons and breathers

Attractive Bose gases can give rise to a plethora of nonlinear excitations, such as breathers and Peregrine solitons, both of them appearing in a wide spectrum of attractive media. Peregrines, however, have far-reaching implications in extreme wave phenomena due to their link to rogue waves. Moreover, they are particularly remarkable since they can be considered as breathers with infinite modulation period. In addition to being far less explored than nonlinear waves in repulsive Bose-Einstein condensates (BECs), the generation of such structures is hindered by wave collapse phenomena. This is circumvented by employing particle imbalanced binary BEC mixtures, that can be reduced to a single effective attractive Bose gas. Here, we generalize such a reduction to arbitrary particle imbalanced multi-component BECs, leading to an even more controllable generation of Peregrines in the effective attractive minority components. This is demonstrated in our joint theoretical and experimental work, where different types of vector Peregrines are nucleated in suitably selected three-component BECs of ⁸⁷Rb. The reduction scheme provides also a handle on the suitable conditions for identifying nonlinear breathers, such as the Akhmediev breather.