Wang Yunfei, Du Huiying, Li Yuqing, Mei Feng, Hu Ying, Xiao Liantuan, Ma Jie, Jia Suotang
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, China.
Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, China.
Light Sci Appl. 2023 Feb 28;12(1):50. doi: 10.1038/s41377-023-01103-8.
The Feynman-Tan relation, obtained by combining the Feynman energy relation with the Tan's two-body contact, can explain the excitation spectra of strongly interacting K Bose-Einstein condensate (BEC). Since the shift of excitation resonance in the Feynman-Tan relation is inversely proportional to atomic mass, the test of whether this relation is universal for other atomic systems is significant for describing the effect of interaction in strongly correlated Bose gases. Here we measure the high-momentum excitation spectra of Cs BEC with widely tunable interactions by using the second- and third-order Bragg spectra. We observe the backbending of frequency shift of excitation resonance with increasing interaction, and even the shift changes its sign under the strong interactions in the high-order Bragg spectra. Our finding shows good agreement with the prediction based on the Feynman-Tan relation. Our results provide significant insights for understanding the profound properties of strongly interacting Bose gases.
通过将费曼能量关系与谭的两体接触相结合得到的费曼 - 谭关系，可以解释强相互作用钾玻色 - 爱因斯坦凝聚体（BEC）的激发光谱。由于费曼 - 谭关系中激发共振的位移与原子质量成反比，因此测试该关系对于其他原子系统是否通用，对于描述强关联玻色气体中的相互作用效应具有重要意义。在此，我们利用二阶和三阶布拉格光谱测量了具有广泛可调相互作用的铯BEC的高动量激发光谱。我们观察到随着相互作用增加，激发共振频移出现回弯现象，甚至在高阶布拉格光谱的强相互作用下频移改变了符号。我们的发现与基于费曼 - 谭关系的预测吻合良好。我们的结果为理解强相互作用玻色气体的深刻性质提供了重要见解。
