• DOI:10.1103/PhysRevA.104.053315
• Corpus ID: 235790513

Effect of Rashba spin-orbit and Rabi couplings on the excitation spectrum of binary Bose-Einstein condensates

@article{Ravisankar2021EffectOR,
  title={Effect of Rashba spin-orbit and Rabi couplings on the excitation spectrum of binary Bose-Einstein condensates},
  author={R. Ravisankar and H. Fabrelli and Arnaldo Gammal and Paulsamy Muruganandam and Pankaj Kumar Mishra},
  journal={Physical Review A},
  year={2021}
}

• R. Ravisankar, H. Fabrelli, +2 authors P. Mishra
• Published 9 July 2021
• Physics
• Physical Review A

We present the collective excitation spectrum analysis of binary Bose-Einstein condensates (BECs) with spin-orbit (SO) and Rabi couplings in a quasi-two-dimensional system. In particular, we investigate the role of SO and Rabi coupling strengths in determining the dynamical stability of the coupled BECs using Bogoliubov-de Gennes (BdG) theory. Using the eigenergy of BdG spectrum, we confirm the existence of phonon, roton, and maxon modes with weak repulsive intraand interspecies contact interactions. The depth of the minimum corresponding to the roton mode depends strongly on the coupling strength. We find that the increase of the SO coupling leads to instability, while the increase in the Rabi coupling stabilizes the system. Also the eigenvectors of BdG spectrum indicates the presence of density like mode in the stable regime and spin like modes in unstable regimes. A phase diagram demonstrating the stability regime in the plane of SO and Rabi coupling strengths is obtained. Finally, we complement the observation of the excitation spectrum with the direct numerical simulation results of coupled Gross-Pitaevskii equations.