2014/04/22 by G. Edward Marti, Andrew MacRae, Ryan Olf +3 · 1 citation
Physics and Astronomy · #cond-mat.quant-gas #physics.atom-ph #quant-ph
paper · pdf · doi:10.1103/physrevlett.113.155302
published as Phys. Rev. Lett. 113, 155302 (2014) · 5 pages, 3 figures
arxiv created 2014/04/22 · arxiv updated 2015/01/27
We measure the mass, gap, and magnetic moment of a magnon in the ferromagnetic F=1 spinor Bose-Einstein condensate of 87Rb. We find an unusually heavy magnon mass of 1.038(2)stat(8)sys times the atomic mass, as determined by interfering standing and running coherent magnon waves within the dense and trapped condensed gas. This measurement is shifted significantly from theoretical estimates. The magnon energy gap of h× 2.5(1)stat(2)sys Hz and the effective magnetic moment of -1.04(2)stat(8) μ_\textrmbare times the atomic magnetic moment are consistent with mean-field predictions. The nonzero energy gap arises from magnetic dipole-dipole interactions.