Rydberg原子研究的新方法

本文首次用非简并四波混频测量了钠原子的Rydberg态系列光谱,并就其某一条谱线在不同压力下的碰撞加宽进行研究.     

Ru原子Rydberg态的能级结构

本文描述用激光共振激发-场电离方法测量Ru原子的4d⁷(⁴F)ns系列和4d⁷(⁴F)nd系列Rydberg态的能级结构,对可能的多重态的相对谱线强度进行了计算。理论计算与实验结果符合得很好,由此可以确定出观测到的各谱线的光谱项。 关键词：     

铯Rydberg原子Stark态的避免交叉

在磁光阱中利用双光子激发制备49S铯Rydberg原子,研究了超冷49S态原子在外加电场中的Stark效应和nS态原子与(n-4)多重态之间的避免交叉现象.利用态选择脉冲场电离方法测量并获得了避免交叉点附近的离子谱,测量了避免交叉点附近离子谱的变化情况,并观察到避免交叉点附近由相互作用导致的态转移现象.     

调制激光场中Rydberg原子的电磁感应透明

本文主要研究了调制探测激光场中铯Rydberg 原子阶梯型三能级系统的电磁感应透明(EIT) 效应. 铯原子基态6S_1/2, 第一激发态6P_3/2 和Rydberg 态形成阶梯型三能级系统, 探测光作用于6S_1/2 (F = 4)→6P_3/2(F' = 5) 的跃迁, 耦合光在Rydberg 跃迁线6P_3/2→49S_1/2 附近扫描, 形成Rydberg 原子EIT. 当对探测光频率施加一个几kHz 的调制时, 调制解调后的EIT 信号分裂为两个峰, 双峰间距与调制频率无关,而与调制幅度导致的失谐量大小(频率调制幅度) 成正比, 双峰间隔的一半等于探测光频率调制幅度的λ_p/λ_c = 1.67 倍. 实验结果与理论计算相一致. 本文的研究结果可应用于激光线型和频率抖动的实时监测.     

平行电磁场中的Rydberg锂原子吸收谱的模型势计算

用B样条基组展开方法结合模型势计算了Rydberg锂原子在平行电磁场下的振子强度谱. 径向和角向均采用高阶Ｂ样条基组.计算结果与已有的实验结果符合得很好.利用分波分析法,对部分谱线的振子强度的强弱进行了分析. 本文方法简单有效，易于推广到交叉电磁场中Rydberg原子的精确谱的计算. 关键词： B样条 能谱 振子强度 平行电磁场 Rydberg原子     

氦原子Rydberg态10G—10M磁精细结构的计算

通过自洽迭代求解Hartree方程，得到了氦原子1snl组态下的严格数值解波函数，以此构造LS耦合谱项(支项)波函数作为基矢.采用线性变分法，同时考虑交换作用和Breit-Bethe近似下的磁相互作用项，计算了氦Rydberg态10G—10M系列能级的磁精细结构，计算结果很好地符合已有的实验值.对计算方法的进一步改进提出了设想和讨论. 关键词： 氦原子 Rydberg态 磁精细结构 自洽迭代     

70S超冷Cs Rydberg原子的动力学演化

利用双光子激发超冷原子获得70S超冷Cs Rydberg原子, 采用脉冲场电离法使Rydberg原子电离, 并用微通道板测量Rydberg原子的信号. 改变激发光和电离电场脉冲的延迟时间和激发光脉冲的宽度, 研究70S超冷Cs Rydberg原子之间的相互作用和动力学演化过程. 利用黑体辐射导致的态转移和相互作用碰撞电离解释了实验结果,实验结果和理论相一致.     

超冷铯Rydberg原子寿命的测量

本文从实验上采用两步激发超冷基态原子获得超冷Rydberg原子,通过选择场电离的方法获得超冷Rydberg原子的离子信号.改变延迟时间测得Rydberg原子布居数随时间的变化关系,用两种方法拟合实验数据得到36D和34S态原子的有效寿命,与现有理论结果一致. 关键词： Rydberg原子 寿命 黑体辐射 场电离     

超冷nS Rydberg原子的态转移

本文从实验上研究了超冷nS Rydberg原子在外电场脉冲作用下的态转移现象. 采用双光子激发超冷基态原子制备超冷Rydberg原子, 通过脉冲场电离法探测超冷Rydberg原子的离子信号, 实验研究了由外加脉冲电场产生的nS能级和多重态的避免交叉, 获得了在外电场脉冲作用下nS态原子的态转移现象, 实验与理论计算的结果相一致. 关键词： Rydberg原子 态转移 能级避免交叉     

弱射频场中Rydberg原子的电磁感应透明

在铯原子室温蒸气池中研究了弱射频场中Rydberg原子阶梯型三能级系统的电磁感应透明(EIT)效应.铯原子基态6S_(1/2)、第一激发态6P_(3/2)和Rydberg 48D_(5/2)态形成阶梯型三能级系统,探测光共振作用于6S_(1/2)(F=4)→6P_(3/2)(F′=5)的跃迁,耦合光在Rydberg跃迁线6P_(3/2)(F′=5)→48D_(5/2)附近扫描,形成Rydberg原子EIT.当对铯原子施加一个80 MHz的弱射频电场时,48D_(5/2)Rydberg原子的EIT光谱发生Stark频移和分裂,同时产生由射频场调制Rydberg能级的偶数级边带,测量结果与Floquet理论模拟的结果相符合.同时,改变弱射频电场的频率研究了铯Rydberg能级的自电离效应对Rydberg原子Stark谱的影响,据此,我们提出将电极板置于铯原子蒸气池内的方案以减少自电离效应的影响.在弱射频Stark谱中,mj=5/2的Stark谱与mj=1/2,3/2的二级边带形成多个能级交叉,这些能级交叉点提供了一种基于原子的精确校准射频电场的新方法.     

镓原子的Stark能级结构

里德堡原子的Stark效应在偶极偶极相互作用、量子信息和量子调控等方面具有潜在的应用前景. 本文首先根据零场时镓原子的能级数据, 通过非线性拟合方法获得了镓原子各态的量子亏损, 仔细分析了量子亏损随主量子数的变化特征; 然后利用Numerov算法计算了镓原子的径向波函数; 最后采用矩阵对角化方法, 数值计算了镓原子高里德堡态在场强范围F=0-3000 V·cm^{- 1}时n=7和n=18附近的Stark能级结构. 结果显示在主量子数n=7多重态以上的能级结构中, (n+1)P态的能级接近并大于nD态的能级, 在n=7多重态以下的能级结构中, (n+1)P态的能级接近并小于nD态的能级. 这一现象不同于通常的碱金属原子的Stark结构, 论文对该现象及其他Stark能级结构特征进行了详细分析, 为相关研究工作提供了重要参考价值.     

High-precision three-dimensional Rydberg atom localization in a four-level atomic system

Rydberg atoms have been widely investigated due to their large size, long radiative lifetime, huge polarizability and strong dipole-dipole interactions. The position information of Rydberg atoms provides more possibilities for quantum optics research, which can be obtained under the localization method. We study the behavior of three-dimensional(3 D)Rydberg atom localization in a four-level configuration with the measurement of the spatial optical absorption. The atomic localization precision depends strongly on the detuning and Rabi frequency of the involved laser fields. A 100% probability of finding the Rydberg atom at a specific 3 D position is achieved with precision of ～0.031λ. This work demonstrates the possibility for achieving the 3 D atom localization of the Rydberg atom in the experiment.     

氖原子奇宇称里德堡能级的理论计算

本文依据最弱受约束电子势模型理论,计算了氖原子1s22s22p5(2Po3/2)ns 2[3/2]o1,2(n=3～50) 和 1s22s22p5(2Po3/2)nd 2[1/2]o0,1(n=3～50)里德堡系列能级和量子亏损.计算结果与已有的51个实验数据符合得很好,并预言了141个能级的位置.     

氖原子奇宇称里德堡能级的理论计算

本文依据最弱受约束电子势模型理论,计算了氖原子1s22s22p5(2Po3/2)ns 2[3/2]o1,2(n=3-50) 和 1s22s22p5(2Po3/2)nd 2[1/2]o0,1(n=3-50)里德堡系列能级和量子亏损。计算结果与已有的51个实验数据符合得很好,并预言了141个能级的位置。     

基于Rydberg原子天线的太赫兹测量

Rydberg原子在微波和太赫兹频段具有极大的电偶极矩,利用量子干涉效应可实现对该频段电磁波场强的高灵敏探测,理论上灵敏度可达到远高于现有探测技术的水平.基于Rydberg原子量子效应的电磁场探测及精密测量技术在太赫兹的场强和功率计量、太赫兹通信和太赫兹成像等方面有着巨大的应用前景.本文回顾了基于Rydberg原子量子干涉效应实现电磁波电场自校准和可溯源测量的基本理论和实验技术,详细介绍了基于Rydberg原子的高灵敏太赫兹场强测量、太赫兹近场高速成像和太赫兹数字通信的基本原理和技术方案.最后简单介绍了本研究团队正在开展的基于Rydberg原子的太赫兹探测工作.     

Bohmian picture of Rydberg atoms

Unlike the previous theoretical results based on standard quantum mechanics that established the nearly elliptical shapes for the centre-of-mass motion in Rydberg atoms using numerical simulations, we show analytically that the Bohmian trajectories in Rydberg atoms are nearly elliptical.     

Resonant-interaction-induced Rydberg antiblockade and its applications

Different from the conventional Rydberg antiblockade (RAB) regime that either requires weak Rydberg-Rydberg interaction (RRI), or compensates the RRI-induced energy shift by introducing off-resonant interactions, we show that RAB regime can be achieved by resonantly driving the transitions between ground state and Rydberg state under strong RRI. The Rabi frequencies are of small amplitude and time-dependent harmonic oscillation, which plays a critical role for the presented RAB. The proposed unconventional RAB regime is used to construct high-fidelity controlled-Z (CZ) gate and controlled-not (CNOT) gate in one step. Each atom requires single external driving. And the atomic addressability is not required for the presented unconventional RAB, which would simplify experimental complexity and reduce resource consumption.     

An effective quantum defect theory for the diamagnetic spectrum of barium Rydberg atom

A theoretical calculation is carried out for the spectrum of barium Rydberg atom in an external magnetic field. Using an effective approach incorporating quantum defect into the centrifugal term in the Hamiltonian, we reexamine the reported spectrum of barium Rydberg atom at a magnetic field of 2.89 T [J. Phys. B 28 L537 (1995)]. Our calculation employs B-spline basis expansion and complex coordinate rotation techniques. For single photon absorption from the ground 6s² to 6snp Rydberg states, the spectrum is not influenced by quantum defects of channels ns and nd. The calculation is in agreement with the experimental observation until the energy reaches E=-60 cm^-1. Up beyond in energy, closer to the threshold, the calculated and experimental results do not agree with each other, possible reasons for their discrepancies are discussed. Our study affirms an energy range where the diamagnetic spectrum of barium atom can be explained thoroughly using a hydrogen model potential.     

Stark spectra of Rydberg states in atomic cesium in the vicinity of n=18

The Stark structures in a cesium atom around n=18 are numerically calculated. The results show that the components of 20D states with a small azimuthal quantum number |m| shift upward a lot, and those with a large |m| shift downward a little within 1100 V/cm. All components of P states shift downward. Experimental work has been performed in ultracold atomic cesium. Atoms initially in 6P3/2 state are excited to high-n Rydberg states by a polarization light perpendicular to the field, and Stark spectra with |m|=1/2,3/2,5/2 are simultaneously observed with a large linewidth for the first time. The observed spectra are analyzed in detail. The relative transition probability is calculated. The experimental results are in good agreement with our numerical computation.