Eur. Phys. J. D (2013) 67: 260
https://doi.org/10.1140/epjd/e2013-40635-x

Regular Article

Dynamics of highly unbalanced Bose-Bose mixtures: miscible vs. immiscible gases

INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, 38123 Povo, Italy

^a e-mail: recati@science.unitn.it

Received: 10 May 2013
Received in final form: 18 October 2013
Published online: 12 December 2013

Abstract

We study the collective modes of the minority component of a highly unbalanced Bose-Bose mixture. In the miscible case the minority component feels an effective external potential and we derive an analytical expression for the mode frequencies. The latter is independent of the minority component interaction strength. In the immiscible case we find that the ground state can be a two-domain walls soliton. Although the mode frequencies are continuous at the transition, their behaviour is very different with respect to the miscible case. The dynamical behaviour of the solitonic structure and the frequency dependence on the inter- and intra-species interaction is numerically studied using coupled Gross-Pitaevskii equations.