非谐阱中囚禁离子亚多普勒冷却的理论研究

项目名称： 非谐阱中囚禁离子亚多普勒冷却的理论研究

项目编号： No.11304387

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 吴春旺

作者单位： 中国人民解放军国防科学技术大学

项目金额： 25万元

中文摘要： 作为一种新型的离子阱构型，非谐阱在离子纵向运动方向上引入了高次势能项，使囚禁势的形状在底部更为平坦，这样就保证了离子在阱中均匀排列，克服了谐势阱中离子数目增多时的"之"字形相变（zig-zag phase transition）问题。由于非谐阱中离子的动力学过程有更为复杂的形式，运动能谱中也引入了一定的非线性，已有的亚多普勒冷却技术并不能直接应用于非谐阱中离子纵向运动模式的深度冷却。本项目旨在考虑高次势能项的影响，建立非谐阱中离子冷却的物理模型，通过引入更为灵活的激光频率调节方式以及新的反馈机制，对适用于谐势阱的具有代表性的边带冷却、反馈冷却两类方案分别进行适当改进，使之适用于非谐阱中离子的亚多普勒冷却。相应研究不但可以为非谐阱中大规模离子精确的量子态操控提供理论和技术积累，同时也将对量子光学、量子度量学等研究方向起到积极的推动作用。

中文关键词： 量子计算；囚禁离子；非谐阱；反馈冷却；相干冷却

英文摘要： As a new style of ion trap, the anharmonic trap introduces some higher-order terms in the longitudinal direction of the ions' trapping potential, which makes the potential have a more flatter bottom and the ions have a nearly uniform neighboring distance, thus avoiding the zig-zag phase transition when the ion number is large for the harmonic trap case. Because the ions in the anharmonic trap have a more complex dynamic process and a nonlinear motional spectrum, the existing sub-Doppler cooling schemes cannot be directly applied to the deep cooling of the longitudinal modes of the ions' motion. In this project, we will consider the effects of the higher-order potential terms and construct the physical model of the laser cooling in the anharmonic trap. By introducing the more flexible adjusting means of the laser frequencies and some new feedback control mechanisms, we will improve the two typical kinds of existing sub-Doppler cooling schemes, i.e., sideband cooling and feedback cooling, make them have the better applicability in the anharmonic trap. These study can not only provide the theoretical and technical basis for the accurate quantum-state manipulation of large-scale ion array in the anharmonic trap, but also help to push many research areas (e.g. quantum optics and quantum metrology) forward.

英文关键词： quantum computing；trapped ions；anharmonic trap；feedback cooling；coherent cooling