%0 Journal Article
%T Center motions of nonoverlapping condensates coupled by long-range dipolar interaction in bilayer and multilayer stacks
%A C. C. Huang
%A W. C. Wu
%J Physics
%D 2012
%I arXiv
%R 10.1103/PhysRevA.82.053612
%X We investigate the effect of anisotropic and long-range dipole-dipole interaction (DDI) on the center motions of nonoverlapping Bose-Einstein condensates (BEC) in bilayer and multilayer stacks. In the bilayer, it is shown analytically that while DDI plays no role in the in-phase modes of center motions of condensates, out-of-phase mode frequency ($\omega_o$) depends crucially on the strength of DDI ($a_d$). At the small-$a_d$ limit, $\omega_o^2(a_d)-\omega_o^2(0)\propto a_d$. In the multilayer stack, transverse modes associated with center motions of coupled condensates are found to be optical phonon like. At the long-wavelength limit, phonon velocity is proportional to $\sqrt a_d$.
%U http://arxiv.org/abs/1206.2201v1