物理学报2016，Vol.65Issue(6)：16-24,9.DOI:10.7498/aps.65.060302
基于垂直引线和调制电流的三线环形磁导引
Three wire toroidal magnetic guide based on the vertical leads and ac current mo dulation
程俊 1张敬芳 2许忻平 1蒋小军 1李晓林 1张海潮 2王育竹1
作者信息
- 1. 中国科学院上海光学精密机械研究所，量子光学重点实验室，上海 201800
- 2. 中国科学院大学，北京 100080
- 折叠
摘要
Abstract
A new scheme to create a closed toroidal magnetic waveguide for deBroglie wave on a single layer atom chip is proposed and there is no zero magnetic field along the guide center. The guide is a two-dimensional magnetic trap for trapping weak-field seeking states of atoms with a magnetic dipole moment. The designed wire structure on the atom chip consists of three concentric and isometric ring wires, and six vertical current leads of the three ring wires. By using the through silicon via technology, the current leads can be made perpendicular to the atom chip surface instead of being generally arranged side by side on the chip surface. Compared with the general wiring way, the vertical lead way has two advantages. One is that each ring wire gap caused by the current leads is substantially smaller than the distance between the ring wires, which permits the generation of a closed toroidal magnetic guide near the atom chip surface when dc currents are supplied to the three ring wires. The other is that the distance between two leads of each ring wire is considerably reduced, resulting in the fact that the magnetic perturbation of the leads to the whole toroidal magnetic guide is negligible. We numerically calculate the magnetic field distribution generated by our wire layout when dc currents are applied, and it is shown that a closed and tight toroidal magnetic guide is formed near the atom chip surface. However, there are zero magnetic fields existing along the center of the toroidal guide, which leads to Majorana spin flips from trapped magnetic substate to an un-trapped magnetic sub-state. According to the time-orbiting-potential principle, we propose an ac current modulation method, which is simple and stable, to reduce the atom losses and suppress the atomic decoherence in the toroidal magnetic guide. We deduce the ac current expressions for the case of three isometric infinite straight wires and apply the ac modulation current expressions directly to our three ring wire structure. The numerical calculation results show that the closed toroidal guide does no longer have zero magnetic fields near the magnetic field minimum, and that the magnetic field fluctuation of the guide is smaller. Based on the vertical leads and ac current modulation, the closed toroidal wave guide with no zero magnetic field along the guide center can be generated near the atom chip surface. This scheme has important scientific significance and engineering value for developing the cold atomic chip gyroscope.关键词
环形磁导引/原子芯片/硅通孔技术/交流调制Key words
toroidal magnetic guide/atom chip/through silicon via/ac current modulation引用本文复制引用
程俊,张敬芳,许忻平,蒋小军,李晓林,张海潮,王育竹..基于垂直引线和调制电流的三线环形磁导引[J].物理学报,2016,65(6):16-24,9.
