共查询到20条相似文献,搜索用时 93 毫秒
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在原子的能级跃迁和光电效应的教学中,经常遇到光子与原子或电子等粒子的相互作用.笔者在此对光子与粒子间的相互作用做简单的分析. 相似文献
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本文利用一维有限光子晶体的模函数展开场算符,确定光与物质相互作用的Hamilton量,从而得到两能级原子自发辐射衰减的动力学方程。未借助马尔科夫近似,我们用数值计算的方法直接求解了原子与场随时间演化的动力学方程,发现在自发辐射过程的最初几个光学周期的时间内,自发衰减速率随时间的变化存在一系列脉冲形状的峰。由于作用于原子的场是一维光子晶体中历经多重反射的场的相干迭加的结果,原子的衰减行为敏感地依赖于多重反射场在原子所在位置的干涉。这种干涉性质依赖于光子晶体的结构。改变光子晶体的结构,使原子的跃迁频率位于光子晶体的禁带中、导带中或缺陷模频率处,可使原子的自发辐射得到抑制或增强。 相似文献
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原子光谱技术作为现代分析检测技术中的一个重要组成部分,在分析领域中占据着举足轻重的地位,而其发展也反映了分析技术的不断改革与创新。综述了中国原子光谱技术近15年来(2000年—2014年)的研究与应用进展。内容涉及原子光谱的多个分支领域,包括原子发射光谱(atomic emission spectrometry,AES),原子吸收光谱(atomic absorption spectrometry,AAS),原子荧光光谱(atomic fluorescence spectrometry,AFS),X射线荧光光谱(X-ray fluorescence spectrometry, XRF)以及原子质谱(atomic mass spectrometry,AMS)五种原子光谱技术,重点关注各技术在检测方法上的创新及其在环境样品、生物样品、食品饮料以及地质材料等相关领域中的应用,并对原子光谱分析中利用到的各种联用技术进行了简要介绍。最后展望了今后我国原子光谱技术的发展方向。 相似文献
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在低Q值腔内,原子相干态在一些特定时刻可以演化为原子薛定谔猫态.讨论了在这种原子薛定谔猫态中原子角动量的涨落和高阶涨落.根据不确定性原理,进一步研究了原子角动量的压缩和高阶压缩性质及其演化.研究表明,原子薛定谔猫态可以被压缩到二阶和六阶,但不能被压缩到四阶.当原子薛定谔猫态中被叠加的原子相干态数为无限多项时,其压缩特性与原子相干态相同.
关键词:
原子相干态
薛定谔猫态
角动量压缩
Bloch态 相似文献
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《Physics letters. A》2019,383(20):2409-2415
This work presents a theoretical investigation on the electronic properties of double atomic carbon chains bridging graphene electrodes with density functional theory in combination with non-equilibrium Green's function. The influence of strain on the conductance of atomic carbon chains is significant. However, the coupling effect between adjacent chains dominates the intrinsic transport of double atomic carbon chains. For the coupled double atomic chains, the electron conductance of even-numbered atomic chains is significantly enhanced, while the electron conductance of odd-numbered atomic chains decreases to a certain degree, and the dependence of the conductance of double atomic chains on electrode configuration is stronger than the corresponding single atomic chain. More intriguingly, the coupled double atomic chains exhibit excellent spin-filtering properties with antiparallel spins on two electrodes. The current spin polarization stems from the coupling-induced changes of electron density and band offset reaches 100%. The coupled double atomic carbon chains have great potential application in spintronic devices and carbon-based field-effect transistors. 相似文献
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介绍了原子物质波的聚焦的基本原理,即原子透镜的工作原理,又对几种类型的原子透镜及其对原子物质波聚焦的优劣性进行了介绍,描述了原子透镜在原子光学中的应用。 相似文献
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We study the interaction of a V-type three-level atom with a two-mode field through the two-photon interaction when the atom is initially in the upper state
and the initial field is in the two-mode squeezed vacuum state. The influence of the atomic motion on the evolution of the
atomic Q-function and atomic Wehrl entropy is examined. The results show that the atomic motion and the mode structure play important
roles in the evolution of the atomic Q-function, atomic Wehrl entropy, and marginal atomic Wehrl entropy. 相似文献
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本文提出一种利用磁光阱冷却捕获技术制备低速、连续、单色性好原子束的方法及技术.采用3维磁光阱从背景Rb蒸汽中捕获Rb87原子进行冷却、捕获形成原子云团,利用在纵向方向上结构设计的小孔将冷原子云团推出形成冷原子束,并在原子束行进方向上采用2维光学黏胶对原子束进行准直,采用态制备激光对其进行态制备,全部制备到Rb87原子的基态能级|F=1>上,从而为原子惯性技术(原子干涉仪、原子重力仪、原子加速度计)、原子频标(原子钟)提供低速、连续、单色性好的原子束.文章对于制备技术的实验系统及实验结果进行了详细的阐述. 相似文献
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We generalize the conception of quantum leakage for the atomic collective excitation states. By making use of the atomic coherence
state approach, we study the influence of the atomic spatial motion on the symmetric collective states of 2-level atomic ensemble
due to inhomogeneous coupling. In the macroscopic limit, we analyze the quantum decoherence of the collective atomic state
by calculating the quantum leakage for a very large ensemble at a finite temperature. Our investigations show that the fidelity
of the atomic system will not be good in the case of atom numberN→∞. Therefore, quantum leakage is an inevitable problem in using the atomic ensemble as a quantum information memory. The
detailed calculations shed theoretical light on quantum processing using atomic ensemble collective qubit. 相似文献
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High-resolution atomic channeling using velocity-controlled atoms may be able to overcome precision limitations of the conventional
atom lithography. We have experimentally clarified the dependence of line width and contrast of atomic patterns in the channeling
region on the velocity spread of the atomic source for the first time. Thermal or velocity-selected atomic beams prepared
with a one-dimensional magneto-optical trap were employed as the atomic sources. We investigated the channeling characteristics
by measuring the frequency shifts of the atomic absorption spectra in an intense standing wave light field. As a result, we
can show that narrower line width and higher contrast atomic patterns are obtained as the velocity spread becomes narrower.
An atomic pattern with an estimated line width of 57 nm was generated when the velocity spread of the atomic source was almost
50 m/s, that is, 1/6 that of the thermal beam.
Received: 16 June 2001 / Published online: 7 November 2001 相似文献
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导数原子光谱分析新技术研究进展 总被引:4,自引:0,他引:4
孙汉文 《光谱学与光谱分析》2003,23(2):386-390
本文评介了导数测量技术在原子光谱分析中的应用研究进展。介绍了常规原子光谱信号模型及其原子光谱信号的导数模型;讨论了原子发射光谱和原子吸收光谱分析导数测量新技术原理及其分析特性。介绍了导数原子光谱技术在生物样品、环境样品、药物分析、食品饮料、金属及合金样品痕量金属元素分析中的应用。基于信号强度随时间变化的新型导数原子光谱分析新技术较常规原子光谱分析,其灵敏度和基线稳定性显著提高、检出限明显改善,在痕量和超痕量金属元素分析领域有着广阔的应用前景。 相似文献