本文關(guān)鍵詞：超冷原子的產(chǎn)生與操控　出處：《中國(guó)科學(xué)技術(shù)大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 流體力學(xué)膨脹 Feshbach共振 BEC-BCS渡越 調(diào)制轉(zhuǎn)移光譜 玻色愛(ài)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(guān)于強(qiáng)相互作用費(fèi)米氣體的流體力學(xué)膨脹的實(shí)驗(yàn)研究。利用834G附近的寬Feshbach共振,我們?cè)谘┣研凸廒逯兄苽淞嗽訑?shù)為le6的6Li超流體。在剩余磁場(chǎng)曲率阱的作用下,原子團(tuán)的自由飛行膨脹會(huì)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(xué)方程來(lái)分析這些膨脹動(dòng)力學(xué)數(shù)據(jù),我們得到了表征費(fèi)米超流的若干重要參數(shù),包括共振點(diǎn)處的Bertsch參數(shù)以及在整個(gè)BEC-BCS渡越區(qū)狀態(tài)方程中的等效冪指數(shù)γ。ξ的實(shí)驗(yàn)測(cè)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(cè)量值0.376(4)。等效冪指數(shù)γ表現(xiàn)為隨相互作用強(qiáng)度非單調(diào)變化的函數(shù),并在BEC,BCS,共振點(diǎn)三個(gè)極限條件下簡(jiǎn)化為已知理論值。其次,我們研究了 6Li原子D1和D2躍遷的調(diào)制轉(zhuǎn)移光譜,揭示了其對(duì)探測(cè)光強(qiáng)度,電光調(diào)制器的調(diào)制頻率和泵浦光的偏振的依賴關(guān)系。實(shí)驗(yàn)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(chǎng)對(duì)調(diào)制轉(zhuǎn)移光譜信號(hào)的影響,發(fā)現(xiàn)它可以顯著增加D2躍遷線的光譜信號(hào)強(qiáng)度。此外,為了證明調(diào)制轉(zhuǎn)移光譜對(duì)頻率調(diào)制光譜的優(yōu)越性,我們做了詳細(xì)的對(duì)比實(shí)驗(yàn)。最后,我們探索了處于深雙勢(shì)阱中的玻色愛(ài)因斯坦凝聚體(BEC)的玻色約瑟夫結(jié)的動(dòng)力學(xué)性質(zhì)。雙阱間的隧穿強(qiáng)度被處于雙阱中對(duì)稱位置的另一團(tuán)BEC所調(diào)控。組分間相互作用將兩團(tuán)BEC的動(dòng)力學(xué)耦合起來(lái),導(dǎo)致了隧穿震蕩中許多有趣的特征。通過(guò)對(duì)囚禁在雙勢(shì)阱中的BEC采用兩模模型近似,并將其和簡(jiǎn)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(dòng)力學(xué),描繪了隧穿動(dòng)力學(xué)的相圖。結(jié)果表明了調(diào)節(jié)雙勢(shì)阱中的BEC隧穿動(dòng)力學(xué)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(xué)位授予單位】：中國(guó)科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：O562

【相似文獻(xiàn)】

相關(guān)博士學(xué)位論文 前1條

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

，

本文編號(hào)：1396934