Leggett-Garg不等式於原子系綜系統的研究

Study of Leggett-Garg inequality in atomic ensembles

于耀淳

指導教授 ： 褚志崧

國立清華大學/理學院/物理學系/碩士(2014年)

摘要

我們利用Leggett-Garg不等式研究一銣(Rubidium)原子系綜系統的量子效應。我們用腔量子電動力學(Cavity quantum electrodynamics)來描述單光子與此原子系綜系統的交互作用，並考慮不同光學厚度(Optical depth)影響下所對應的擁有不同coupling strengths 以及 cavity loss rates的腔量子電動力學系統。我們在腔量子電動力學系統下考慮兩種情況：coupling strengths約等於或遠大於cavity loss rate，在這兩種情況中我們都有觀察到系統違反了Leggett-Garg不等式的現象，顯示了在原子系綜系統中出現了量子效應。在我們未來的研究中，溫度對於原子系綜系統的影響將會成為研究Leggett-Garg不等式的條件之一。

關鍵字

Leggett-Garg不等式 ； 銣原子系綜系統 ； 腔量子電動力學 ； 光學厚度

並列摘要

We utilize Leggett-Garge inequality to study the quantum phenomenon in an atomic ensemble of Rubidium atoms. The interaction between the ensemble and single photons is treated by cavity quantum electrodynamics (cavity QED). Ensembles of different optical depths, corresponding to cavity QED systems with different coupling strengths and cavity loss rates, are considered. In particular, we consider two cases where the coupling strengths are either comparable or much larger than the cavity loss rate. Violation of Leggett-Garge inequality are found in both cases, which demonstrates the presence of quantumness in an atomic ensemble. In future works, effect of temperature of atomic ensembles will be included to study the violation of Leggett-Garge inequality.

並列關鍵字

Cavity quantum electrodynamics ； Optical depth ； coupling strengths ； cavity loss rates

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