Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
Phys Rev Lett. 2012 Sep 14;109(11):115301. doi: 10.1103/PhysRevLett.109.115301. Epub 2012 Sep 12.
In this Letter, we present an experimental study of the collective dipole oscillation of a spin-orbit coupled Bose-Einstein condensate in a harmonic trap. The dynamics of the center-of-mass dipole oscillation is studied in a broad parameter region as a function of spin-orbit coupling parameters as well as the oscillation amplitude. The anharmonic properties beyond the effective-mass approximation are revealed, such as the amplitude-dependent frequency and finite oscillation frequency at a place with a divergent effective mass. These anharmonic behaviors agree quantitatively with variational wave-function calculations. Moreover, we experimentally demonstrate a unique feature of the spin-orbit coupled system predicted by a sum-rule approach, stating that spin polarization susceptibility--a static physical quantity--can be measured via the dynamics of dipole oscillation. The divergence of polarization susceptibility is observed at the quantum phase transition that separates the magnetic nonzero-momentum condensate from the nonmagnetic zero-momentum phase. The good agreement between the experimental and theoretical results provides a benchmark for recently developed theoretical approaches.
在这封信件中，我们呈现了一项关于自旋轨道耦合玻色-爱因斯坦凝聚体在谐振势阱中集体偶极振荡的实验研究。我们研究了质心偶极振荡的动力学，其作为自旋轨道耦合参数以及振荡幅度的函数，涵盖了很宽的参数区域。我们揭示了超越有效质量近似的非谐性质，例如频率随振幅变化以及在有效质量发散处的有限振荡频率。这些非谐行为与变分波函数计算定量吻合。此外，我们通过实验证实了和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和和
