Chevy F, Madison KW, Dalibard J
Laboratoire Kastler Brossel Departement de Physique de l'Ecole Normale Superieure, 24 rue Lhomond, 75005 Paris, France.
Phys Rev Lett. 2000 Sep 11;85(11):2223-7. doi: 10.1103/PhysRevLett.85.2223.
We study the quadrupole oscillation of a Bose-Einstein condensate of 87Rb atoms confined in an axisymmetric magnetic trap, after it has been stirred by an auxiliary laser beam. The stirring may lead to the nucleation of one or more vortices, whose presence is revealed unambiguously by the precession of the axes of the quadrupolar mode. For a stirring frequency Omega below the single vortex nucleation threshold Omega(c), no measurable precession occurs. Just above Omega(c), the angular momentum deduced from the precession is approximately Planck's over 2pi. For stirring frequencies above Omega(c) the angular momentum is a smooth and increasing function of Omega, until an angular frequency is reached at which the vortex lattice disappears.
我们研究了被限制在轴对称磁阱中的87Rb原子玻色-爱因斯坦凝聚体在受到辅助激光束搅拌后的四极振荡。搅拌可能会导致一个或多个涡旋的形成，四极模式轴的进动明确地揭示了这些涡旋的存在。对于低于单涡旋形成阈值Ωc的搅拌频率Ω，没有可测量的进动发生。刚好高于Ωc时，从进动推导出的角动量约为普朗克常数除以2π。对于高于Ωc的搅拌频率，角动量是Ω的平滑递增函数，直到达到一个角频率，此时涡旋晶格消失。
