Excitation spectrum of a mixture of two Bose gases confined in a ring potential with interaction asymmetry

Abstract

We study the rotational properties of a two-component Bose–Einstein condensed gas of distinguishable atoms which are confined in a ring potential using both the mean-field approximation, as well as the method of diagonalization of the many-body Hamiltonian. We demonstrate that the angular momentum may be given to the system either via single-particle, or ‘collective’ excitation. Furthermore, despite the complexity of this problem, under rather typical conditions the dispersion relation takes a remarkably simple and regular form. Finally, we argue that under certain conditions the dispersion relation is determined via collective excitation. The corresponding many-body state, which, in addition to the interaction energy minimizes also the kinetic energy, is dictated by elementary number theory.

Keywords

• Bose–Einstein condensation
• mixtures
• superfluidity
• vector solitons
• 05.30.Jp
• 03.75.Lm