| 题名 | 冷原子的非绝热输运与射频导引 |
| 作者 | 陈东元 |
| 学位类别 | 硕士 |
| 答辩日期 | 2010 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 张海潮 |
| 关键词 | 非绝热输运 剩余振幅 参量冷却 射频导引 |
| 其他题名 | Nonadiabatic Transport and Radio-Frequency Guiding of Cold Atoms |
| 中文摘要 | 由于冷原子输运对冷原子物理和量子信息发展的重要作用，近些年在国际上得到了广泛的关注。本论文介绍我们小组在此领域中实现的两项全新的技术，分别是利用磁四极阱以非绝热方式实现的冷原子快速输运以及利用射频场实现的冷原子导引。 我们利用磁四极阱实现了非绝热的冷原子输运，最短的输运时间达到一个势阱周期的量级。磁四极阱由两组反亥姆霍兹线圈对产生。通过改变线圈中的电流来移动势阱的位置，达到输运原子的目的。实验上，我们以两类速度输运冷原子。第一类是势阱速度对应于原子在阱中的质心运动未被激发，即剩余速度为零。例如在我们的实验中势阱速度为18 cm/s时，最终的原子云速度为0.6 ± 2.7 cm/s，近乎于静止。第二类阱速度处于第一类阱速度之间。选择恰当的阱速可以剔除阱中能量高的原子，从而使具有高剩余速度的原子云温度下降。例如在势阱速度为28 cm/s时, 最终的原子云具有很大出射速度, 为58.6 ± 1.5 cm/s。 另一项技术是冷原子的射频场导引。我们利用通入射频电流的四根平行导线来产生射频场，一对亥姆霍兹线圈产生静磁偏置场。理论上讲，射频导引的优势是能够约束静磁场中的强场趋向态，并且中心处不存在由于非绝热的自旋反转碰撞产生的零点损失。我们在实验上观察到了射频导引的原子信号，并且成功实现了强场趋向态原子的导引。 |
| 英文摘要 | The transport of cold atoms has been widely researched these years, which is promising in the realization of new experiments in atomic physics and the development of quantum information. Recently, our group realized two new techniques on this field: the nonadiabatic transport of cold atoms using a magnetic quadrupole potential and the atomic guiding using radio frequency field. We experimentally demonstrated the transport of cold atoms in a magnetic quadrupole trap in the nonadiabatic regime on the order of the trap period. The trap potential velocity was controlled by varying the currents of the two pairs of anti-Helmholtz coils. We efficiently transported cold atoms with two velocity regimes. One set of trap velocities corresponds to little excitation of center-of-mass mode. After the transport, the cloud of atoms is almost at rest. For example, with a potential velocity of 18 cm/s, the final velocity of a cold atom cloud is 0.6 ± 2.7 cm/s. Another set of trap velocities is among velocities of the first type mentioned above. For example, with a potential velocity of 28 cm/s, the final velocity of a cold atom cloud is 58.6 ± 1.5 cm/s. The trap motion with proper velocity could expel energetic atoms from the trap, resulting in a decline in temperature of high residual velocity atoms. We have realized an atomic guiding using radio frequency (RF) field. The guiding is formed in a configuration of Ioffe-Prichard trap with the Ioffe bars carrying a RF current and Hemholtz coils carrying direct currents. Theoretically, it can not only trap strong-field-seeker atoms, but also avoid the atom loss caused by Majorana transition. Experimentally, we observed the guiding of the strong-field-seeker atoms, verifying our theoretical expectations. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16668]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 陈东元. 冷原子的非绝热输运与射频导引[D]. 中国科学院上海光学精密机械研究所. 2010. |
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