超冷原子的产生与操控

发布时间：2018-01-08 11:29

本文关键词：超冷原子的产生与操控　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：在本论文中,我们首先介绍关于强相互作用费米气体的流体力学膨胀的实验研究。利用834G附近的宽Feshbach共振,我们在雪茄型光阱中制备了原子数为le6的6Li超流体。在剩余磁场曲率阱的作用下,原子团的自由飞行膨胀会出现类四极震荡的行为,并可持续到30ms。根据超流流体力学方程来分析这些膨胀动力学数据,我们得到了表征费米超流的若干重要参数,包括共振点处的Bertsch参数以及在整个BEC-BCS渡越区状态方程中的等效幂指数γ。ξ的实验测量值0.42(2)尽管和量子蒙特卡洛算法的模拟值0.42(1)吻合较好,但仍略大于原位高精度测量值0.376(4)。等效幂指数γ表现为随相互作用强度非单调变化的函数,并在BEC,BCS,共振点三个极限条件下简化为已知理论值。其次,我们研究了 6Li原子D1和D2跃迁的调制转移光谱,揭示了其对探测光强度,电光调制器的调制频率和泵浦光的偏振的依赖关系。实验证明吸收谱中的交叉峰更利于激光的频率锁定。我们还研究了磁场对调制转移光谱信号的影响,发现它可以显著增加D2跃迁线的光谱信号强度。此外,为了证明调制转移光谱对频率调制光谱的优越性,我们做了详细的对比实验。最后,我们探索了处于深双势阱中的玻色爱因斯坦凝聚体(BEC)的玻色约瑟夫结的动力学性质。双阱间的隧穿强度被处于双阱中对称位置的另一团BEC所调控。组分间相互作用将两团BEC的动力学耦合起来,导致了隧穿震荡中许多有趣的特征。通过对囚禁在双势阱中的BEC采用两模模型近似,并将其和简谐束缚BEC的GP方程耦合,我们从数值上研究了 BEC混合体的耦合动力学,描绘了隧穿动力学的相图。结果表明了调节双势阱中的BEC隧穿动力学的可能性。
[Abstract]:In this paper, we first introduce the experimental study on the hydrodynamic expansion of strongly interacting Fermi gas. The wide Feshbach resonance near 834G is used. We have prepared 6Li superfluid with le6 atom number in cigar type optical trap. Under the action of curvature trap of residual magnetic field, the free-flying expansion of atomic clusters will appear quasi quadrupole oscillation behavior. According to the superfluid hydrodynamic equation to analyze these expansion dynamic data, we have obtained some important parameters to characterize Fermi superflow. Including the Bertsch parameters at the common vibration point and the equivalent power exponent 纬. 尉 in the state equation of the whole BEC-BCS transit zone. Although it is in good agreement with the simulation value of Quantum Monte Carlo algorithm 0.42 ~ (1). The equivalent power exponent 纬 is a function of non-monotone variation with the interaction intensity, and the BCS of BECs is obtained in BECs. Under the three limit conditions of the resonance point, the known theoretical values are simplified. Secondly, we study the modulation transfer spectra of the D1 and D2 transitions of 6Li atoms and reveal the intensity of the detected light. The modulation frequency of the electro-optic modulator is dependent on the polarization of the pump light. The experimental results show that the cross peak in the absorption spectrum is more favorable to the frequency locking of the laser. We also study the effect of the magnetic field on the modulation transfer spectrum signal. It is found that it can significantly increase the spectral signal intensity of the D2 transition line. In addition, in order to prove the superiority of the modulation transfer spectrum to the frequency modulation spectrum, we have done a detailed comparative experiment. We have explored the Bose-Einstein condensate (BECs) in a deep double well. The tunneling strength of the double well is regulated by another BEC in the symmetric position of the double well. The interaction between the components coupled the dynamics of the two groups of BEC. This leads to many interesting characteristics of tunneling oscillations. By using two-mode model approximation for BEC trapped in a double potential well, it is coupled with GP equation of harmonic binding BEC. We numerically study the coupling dynamics of BEC mixtures and describe the phase diagram of tunneling dynamics. The results show that it is possible to adjust the BEC tunneling dynamics in double potential wells.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O562

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