饱和铁氧体界面附近的原子Casimir-Polder扭矩效应  

Casimir-Polder Torque Effect of Atom near the Surface of Saturated Ferrite

作　　者：胡悦 曾然[1] 徐思远 陈伟强[1] 李浩珍 杨淑娜 李齐良[1] 羊亚平[2] HU Yue;ZENG Ran;XU Siyuan;CHEN Weiqiang;LI Haozhen;YANG Shuna;LI Qiliang;YANG Yaping(School of Communication Engineering,Hangzhou Dianzi University,Hangzhou 310018,China;Ministry of Education Key Laboratory of Advanced Micro-Structured Materials,School of Physics Science and Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]杭州电子科技大学通信工程学院,杭州310018 [2]同济大学物理科学与工程学院先进微结构材料教育部重点实验室,上海200092

出　　处：《光子学报》2022年第6期428-437,共10页Acta Photonica Sinica

基　　金：浙江省自然科学基金(No.LY21A040003);国家自然科学基金(Nos.61901148,11574068);浙江省属高校基本科研业务费专项资金(No.GK199900299012‐015)。

摘　　要：对二能级原子与饱和铁氧体材料板之间的Casimir-Polder量子真空扭矩进行了研究。利用格林张量推导求得二能级原子与饱和铁氧体之间Casimir-Polder扭矩的表达式。结合不同的原子偶极矩和铁氧体特殊的电磁特性,从原子频率、原子位置、外磁场和圆极化偶极矩极化平面所受微扰等方面对Casimir-Polder扭矩进行分析。结果表明,原子位置和跃迁频率会影响Casimir-Polder扭矩的强度,而扭矩随铁氧体所处外磁场强度的变化特性在不同的原子位置和频率下会呈现非单调的拐点。此外,原子圆极化偶极矩在受到一定的角度微扰下,其扭矩具有回归原旋转平面趋势的平衡稳定性。因此,通过改变铁氧体所处的外磁场环境,可以调控原子的Casimir-Polder扭矩,这为二能级系统旋转态的加速或冷却至量子基态的控制提供一种新方法。The van der Waals–Casimir and Casimir-Polder effects of microscopic particles have been the subject of intensive research in recent years.The zero-point energy quantum fluctuations of the electromagnetic field cause the van der Waals forces;the change of the boundary surface leads to the disturbance of the zero-point energy of the electromagnetic field,and the Casimir force acting on the object can be observed macroscopically.For anisotropic media,the Casimir force may change with the relative direction between the media,and this change leads to the relative rotation,which is called the Casimir torque.The current research on the Casimir effect has involved a variety of anisotropic materials,such as birefringent materials,metamaterials,and anisotropic topological insulators,and the experimental setup for measuring the torque has also been proposed.The Casimir-Polder effect of the two-level atomic system has aroused great interest within the study of quantum optics in recent years.In the presence of boundary of material,the atoms in the ground state or excited state can be affected by the Casimir-Polder potential,and then the Casimir-Polder interaction force emerge,which are also induced by the electromagnetic field of the vacuum fluctuation.Between the boundary of the anisotropic medium and the atom,the Casimir-Polder rotational torque is generated.The vacuum-induced torque effect plays an important role in the fields of physical chemistry,atomic optics and cavity quantum electrodynamics,and it can also result in many potential applications in nanotechnology,such as atomic force microscopes,and reflective elements in atomic optics.The ferrite is a non-metal composite oxide material with ferromagnetism that has been continuously developed in recent years,and its resistivity and dielectric properties show advantages in comparison with conventional magnetic metal.The ferrite has a large magnetic permeability in the high frequency range,so it also has a wide range of uses in the field of high frequency weak current.

关 键 词：量子光学 真空涨落 Casimir-Polder扭矩 饱和铁氧体 二能级原子 

分 类 号：O431.2[机械工程—光学工程]