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

• Published in: New journal of physics Vol. 20; no. 4; pp. 45006 - 45025
• Main Authors: Roussou, A, Smyrnakis, J, Magiropoulos, M, Efremidis, N K, Kavoulakis, G M, Sandin, P, Ögren, M, Gulliksson, M
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 16-04-2018
• Subjects: 03.75.Lm; 05.30.Jp; Angular momentum; Bose-Einstein condensation; Electrons; Excitation spectra; Fysik; Kinetic energy; Matematik; Mathematics; mixtures; Number theory; Physics; superfluidity; vector solitons; vector solitons; superfluidity; mixtures; Bose-Einstein condensation
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/aab599

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.