Absorption resonances in A-type three-level system in cesium vapor cell with buffer gas

We report experimentally the transformation from the electromagnetically induced transparency (EIT) resonance to a dispersion-like signal and eventually to a nearly symmetric absorption resonance as coupling detuning increases in A-type three-level system in the cesium vapor cell with buffer gas at room temperature. The observed absorption resonance occupies some remarkable properties of the strong amplitude and the narrow linewidth in comparison with the case without buffer gas. The relation between linewidth of the enhanced absorption resonance and buffer gas pressure is studied. With pressure increasing, linewidth of the absorption resonance becomes narrow. The sub-natural linewidth is observed in Doppler-broadened cesium vapor cell in our experiment. The experimental results are in qualitative agreement with the numerical simulations.     

High-resolution photoassociation spectroscopy of ultracold Cs2 long-range 0-g state： The external well potential depthHigh-resolution photoassociation spectroscopy of ultracold Cs2 long-range 0-g state： The external well potential depthHigh-resolution photoassociation spectroscopy of ultracold Cs2 long-range 0-g state： The external well potential depth

High-resolution photoassociation spectroscopy is reported using a modulation spectroscopy technology in a cesium atomic magneto-optical trap. The two lowest vibrational levels have been experimentally observed which have been theo- retically predicted in [Phys. Rev. A 75 052501 （2007）]. A new potential curve is obtained by using the Rydberg-Klein-Ress method with a well depth of -82,384 ＋ 0,026 cm-1, which is deeper than the result of previous experiment （-77.909 cm-1） and the theoretical prediction （-81.6445 cm- l ）.     

Investigation of ultracold atoms and molecules in a dark magneto-optical trap

In this paper,ultracold atoms and molecules in a dark magneto-optical trap(MOT) are studied via depumping the cesium cold atoms into the dark hyperfine ground state.The collision rate is reduced to 0.45s-1 and the density of the atoms is increased to 5.6×1011cm-3 when the fractional population of the atoms in the bright hyperfine ground state is as low as 0.15.The vibrational spectra of the ultracold cesium molecules are also studied in a standard MOT and in a dark MOT separately.The experimental results are analyzed by using the perturbative quantum approach.     

Pd团簇熔化的分子动力学模拟

本文运用分子动力学研究钯团簇Pd,(n=13,14,54,55)熔化行为.结果表明:所有Pdn团簇的熔化过程中都有预熔化行为.Pdn团簇的熔点并不是随着原子数目的增加而有着简单的递增关系.Pdn(n=54,55)团簇的预熔化温度区间比较窄.Pdn(n=13,54,55)团簇在熔化过程中有固液共存现象,而Pd14团簇则有表面熔化行为.     

噪声抵消法估计和抑制声呐部位主要自噪声

本文采用修正格型过滤自适应噪声抵消方法，成功地抑制艇艄声呐部位自噪声中的螺旋桨噪声成分等，抑制效果达４０ｄＢ以上。所采用的经改进后的ＬＳＬ算法收敛速度快，精度高，具有宽带抑噪性能。利用上述噪声抵消系统（软件）分析、判别了各噪声源对艇艏声呐部位声场的贡献，在确定主要噪声源方面，获得比较满意的结果。     

The laser-intensity dependence of the photoassociation spectrum of the ultracold Cs2（6S1/2 ＋ 6P1/2） 0＋ long-range molecular state

The high-resolution photoassociation spectrum of the ultracold cesium molecular 0＋ state below the 6S1/2 ＋ 6PI/2 limit is presented in this paper. The saturation of the photoassociation scattering probability is observed from the depen dence of the trap-loss probability on the photoassociation laser intensity. The corresponding resonant line width is also demonstrated to increase linearly with increasing photoassociation laser intensity. Our experimental data have good con sistency with the theoretical saturation model of Bohn and Julienne [Bohn J L and Julienne P S 1999 Phys. Rev. A 60 1].     

超冷铯分子纯长程态转动常数的精密测量

利用调制的俘获损耗光谱技术实验测量了超冷铯分子纯长程0_g^-态的高分辨光谱. 采用双光缔合光谱技术构建了精确的频率差参考信号, 对转动能级的共振频率间隔进行了精确的标定, 获得了转动能级频率间隔与转动量子数的关系. 通过将实验数据拟合到非刚性转动模型, 获得了超冷铯分子纯长程0_g^-态不同振动态的转动常数. 实验结果表明转动常数随振动量子数的增加而线性减小, 线性递减率为-0.41 MHz±0.01 MHz. 关键词： 双光缔合光谱技术 超冷铯分子 转动常数 纯长程态     

云南省卷烟供给模型初探

本文利用１９６０－１９８４年２４年的统计资料，采用逐步回归分析的方法，从影响云南省卷烟供给的五个因素中的，逐步进行筛选，得到一回归方程： Ｑt＝６．６８×１０－８Ｄt０．３２７９９（Ｆt／ｇt） ３．１２３9 对筛选下来的另外三个解释变量也对Ｑt作回归，得第二个归回方程： Ｑt＝２．８１８（Ｐt－Ｃt）０．０５０４·Ｗt ０．５６１４·Ｈt１．５２８３以上述两个模型为依据，对云南省的卷烟供给政策做了评价，由此而得出一些有益的结论．     

冷原子EIT介质的原子数目和温度的测量

简要介绍了我们实验组冷却、俘获87Rb原子的磁光阱装置及冷却俘获过程。采用收集荧光法测得了俘获的冷原子数目,并根据冷原子团尺寸推算出了冷原子团密度。通过在冷原子团下方4 mm,7 mm,10 mm三处设置圆柱形探测光束,在原子自由下落过程中获得了短程飞行时间(TOF)吸收信号,通过数值拟合得到了冷原子的温度。结果表明:俘获的冷原子数目大约为109个,密度大约为1011个/cm3,冷却温度约为200μK,该冷原子团能作为很好的EIT介质。     

先进磁镜装置中径向电场对高能粒子的约束性能研究

本文运用Boris算法对紧凑型聚变反应装置(compact fusion reactor, CFR)中高能a粒子的运动轨道进行了数值模拟,分析了高能a粒子在不同径向电场作用下运动轨道的差异性;探究了不同径向电场对CFR装置中不同位置处a粒子约束性能的影响.研究结果表明,当正、负径向电场强度达到一定临界值时,都能够使高能a粒子很好地约束在CFR装置内部,但不同位置处径向电场强度临界值与a粒子初始条件有关.