Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430 Villetaneuse, France and CNRS, UMR 7538, LPL, F-93430 Villetaneuse, France.
Phys Rev Lett. 2018 Jul 6;121(1):013201. doi: 10.1103/PhysRevLett.121.013201.
We report on the observation of a collective spin mode in a spinor Bose-Einstein condensate. Initially, all spins point perpendicular to the external magnetic field. The lowest energy mode consists of a sinusoidal oscillation of the local spin around its original axis, with an oscillation amplitude that linearly depends on the spatial coordinates. The frequency of the oscillation is set by the zero-point kinetic energy of the BEC. The observations are in excellent agreement with hydrodynamic equations. The observed spin mode has a universal character, independent of the atomic spin and spin-dependent contact interactions.
我们报告了在自旋玻色-爱因斯坦凝聚体中观察到的集体自旋模式。最初，所有自旋都垂直于外磁场。最低能量模式由局部自旋围绕其原始轴的正弦振荡组成，其振荡幅度与空间坐标呈线性关系。振荡的频率由 BEC 的零点动能设定。观察结果与流体动力学方程非常吻合。所观察到的自旋模式具有普遍性，与原子自旋和自旋相关的接触相互作用无关。
