玻色-爱因斯坦凝聚体在一维光晶格中的相位涨落是研究量子相变的重要参量。 在实验和理论上分别获得了凝聚体从光晶格中释放后的密度分布,通过分析比较两者干 涉峰的对比度提取凝聚体在光晶格中的相位涨落。应用这一方法,测量了不同光晶格阱深下凝聚 体的相位涨落。当光晶格阱深从最小值5.6ER变化到30.7ER时,相位涨落从0.29π上升 到0.69π。

For Bose-Einstein condensates in one dimensional optical lattice, the phase fluctuation is a significant quantity in the investigation of quantum phase transition. A method to measure the phase fluctuation was investigated by comparing the contrast of interference peaks obtained from experimental absorption images and simulated data sets. Phase variances of condensates in optical lattices with different depth were measured by this method. The phase fluctuations increase from 0.29π to 0.69π when the depth of optical lattice varies from 5.6ER to 30.7ER.