Multipole quantum droplets in quasi-one-dimensional asymmetric mixtures

Abstract

We study quantum droplets emerging in a quasi-one-dimensional asymmetric mixture of two atomic species with different intra-component coupling constants. We find that such mixtures support a rich variety of multipole quantum droplets, where the macroscopic wavefunction of one component changes its sign and features distinctive multipole structure, while the wavefunction of another component does not have zeros. Such multipole droplets have no counterparts in the reduced single-component model frequently used to describe symmetric one-dimensional mixtures. We study transformations of multipole states upon variation of the chemical potential of each component and demonstrate that quantum droplets can split into separated fundamental states, transform into flat-top multipoles, or into multipole component coupled to flat-top state with several humps on it, akin to anti-dark solitons. Multipole quantum droplets described here are stable in large part of their existence domain. Our findings essentially broaden the family of quantum droplet states emerging in the beyond-meanfield regime and open the way for observation of such heterostructured states in Bose-Bose mixtures.