銣原子玻色愛因斯坦凝結之自旋動力學

Coherent spin dynamics of 87Rb Bose gas

孫立安(Li-An Sun)

指導教授 ： 劉國平

共同指導教授 ： 張銘顯(Ming-Shien Chang)

國立臺灣大學/理學院/物理學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201603032

摘要

當巨觀數量全同玻色子開始進入量子基態時會發生量子相變形成玻色愛因斯坦凝結(玻思凝結)，這些凝聚態的粒子共享同一個波函數並處在同樣的相位。玻思凝結的外在同調性(空間同調性) 可以由兩團凝結態粒子干涉等實驗所證實。本文的研究則著重旋子玻思凝結的內在自旋同調性，我們研究銣原子旋子玻思凝結|F = 1⟩ 之自旋動力學。本篇論文中，我們首先介紹如何在全光阱製備及操縱旋子玻思凝結；第二部分會呈現旋子玻思凝結在不同起始內在自旋居量、以及外加磁場下的同調自旋混合現象。我們觀察到系統自旋居量的同調振盪現象，其震盪維持約1 秒。

關鍵字

銣原子-87 ； 光偶極阱 ； 玻色愛因斯坦凝結 ； 旋子玻思凝結 ； 鐵磁性 ； 自旋混合

並列摘要

A Bose-Einstein condensate (BEC) emerges when a macroscopic number of identical bosons occupying quantum ground state. Those Bose-condensed particles share the same wave function and phase, and coherence of the external (motional) degree of freedom of an atomic BEC was proven by the interference of two clouds of BEC’s. Spionr condensates are a multi-component BEC, which possesses internal spin degree of freedom. In this thesis, we focus
on the coherence of the internal spin degree of freedom, and we study the non-equilibrium coherent spin mixing dynamics in spin-1 BEC of 87Rb atoms. In the first part of this thesis, we briefly introduce how we create and manipulate spinor condensates in an all-optical trap. In the second part, we study the coherent spin mixing signatured by sinusoidal spin population oscillation, with different initial spin population ratios under different magnetic fields. The coherent oscillation was found to persist for 1 sec.

並列關鍵字

rubidium-87 ； optical dipole trap ； Bose-Einstein condensate ； spinor condensates ； ferromagnetism ； spin mixing

參考文獻

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[4] Ming-Shien Chang. Coherent Spin Dynamics of a Spin-1 Bose-Einstein Condensate. PhD thesis, Georgia Institute of Technology, 2006.

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