本文關鍵詞：超冷原子的產(chǎn)生與操控　出處：《中國科學技術大學》2017年博士論文　論文類型：學位論文

  更多相關文章： 流體力學膨脹 Feshbach共振 BEC-BCS渡越 調制轉移光譜 玻色愛因斯坦凝聚 雙阱隧穿 耦合GP方程

【摘要】：在本論文中,我們首先介紹關于強相互作用費米氣體的流體力學膨脹的實驗研究。利用834G附近的寬Feshbach共振,我們在雪茄型光阱中制備了原子數(shù)為le6的6Li超流體。在剩余磁場曲率阱的作用下,原子團的自由飛行膨脹會出現(xiàn)類四極震蕩的行為,并可持續(xù)到30ms。根據(jù)超流流體力學方程來分析這些膨脹動力學數(shù)據(jù),我們得到了表征費米超流的若干重要參數(shù),包括共振點處的Bertsch參數(shù)以及在整個BEC-BCS渡越區(qū)狀態(tài)方程中的等效冪指數(shù)γ。ξ的實驗測量值0.42(2)盡管和量子蒙特卡洛算法的模擬值0.42(1)吻合較好,但仍略大于原位高精度測量值0.376(4)。等效冪指數(shù)γ表現(xiàn)為隨相互作用強度非單調變化的函數(shù),并在BEC,BCS,共振點三個極限條件下簡化為已知理論值。其次,我們研究了 6Li原子D1和D2躍遷的調制轉移光譜,揭示了其對探測光強度,電光調制器的調制頻率和泵浦光的偏振的依賴關系。實驗證明吸收譜中的交叉峰更利于激光的頻率鎖定。我們還研究了磁場對調制轉移光譜信號的影響,發(fā)現(xiàn)它可以顯著增加D2躍遷線的光譜信號強度。此外,為了證明調制轉移光譜對頻率調制光譜的優(yōu)越性,我們做了詳細的對比實驗。最后,我們探索了處于深雙勢阱中的玻色愛因斯坦凝聚體(BEC)的玻色約瑟夫結的動力學性質。雙阱間的隧穿強度被處于雙阱中對稱位置的另一團BEC所調控。組分間相互作用將兩團BEC的動力學耦合起來,導致了隧穿震蕩中許多有趣的特征。通過對囚禁在雙勢阱中的BEC采用兩模模型近似,并將其和簡諧束縛BEC的GP方程耦合,我們從數(shù)值上研究了 BEC混合體的耦合動力學,描繪了隧穿動力學的相圖。結果表明了調節(jié)雙勢阱中的BEC隧穿動力學的可能性。
[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 緯. 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 緯 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.
【學位授予單位】：中國科學技術大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：O562

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1 Mudassar Maraj;超冷原子的產(chǎn)生與操控[D];中國科學技術大學;2017年

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本文編號：1396934