锡原子奇宇称5pnd和5pns J = 1, 2 Rydberg系列的多通道量子亏损理论研究

利用多通道量子亏损理论（MQDT）,对锡原子奇宇称5pnd和5pns组态的J = 1,2简并受扰Rydberg系列能级进行了理论分析研究. 通过拟合实验能级,得到了MQDT优化参数,所得理论能级值与文献报道的实验结果符合得很好. 由算得的通道混合系数,分析讨论了通道相互作用特性,确定了所有能级的原子态命名. 本文结果有助于人们更好地了解锡原子高激发态的能级结构和组态相互作用特性.     

78Kr高自旋态的形状共存

用熔合蒸发反应 58Ni(2 3Na,3p) (Ein=70 Me V)和 58Ni(2 8Si,α4p) (Ein=1 30 Me V)研究了78Kr的高自旋态 ,用美国劳伦斯伯克利国家实验室的γ球测量了实验中产生的瞬时符合事件,对新发现的一个负宇称带用多普勒位移衰减法对 1 0 0 4 ke V(1 0 -→ 8-)和 873ke V(8-→ 6-)作了多普勒展宽谱线形状测量 .得到了负宇称带 1 0 -态能级的寿命τ=(2 .2± 0 .3) ps,8-态能级的寿命τ=(1 .6± 0 .2 ) ps.故可知此负宇称带呈现长椭形变 ,与正宇称带的扁椭形变形状共存. Doppler shift attenuation lifetime measurements were performed in the 58 Ni( 23 Na,3p) reaction at 70 MeV and 58 Ni( 28 Si, α4p) reaction at 130 MeV. By analyzing the Doppler broadened line shapes of the 1 004 keV(10 -→8 -) negative parity transition in coincidence with depopulating transitions, the lifetime of the 10 - state has been deduced as τ =(2.2±0.3) ps. A similar analysis of 873 keV(8 -→6 -)transition gave values of τ =(1.6±0.2)...     

V型系统中自发辐射相干效应对无反转粒子数激光产生条件的影响

本文从理论上讨论了自发辐射相干效应 (Spontaneously Generated Coherence, 简记为SGC) 对V型原子中无反转激光 (Lasing Without Inversion, 简记为LWI) 产生条件的影响.在V型原子中,当其上两个能级为简并或近简并能级时 (如Zeeman分裂能级),会出现SGC效应.研究表明,在SGC效应起作用的情况下,无需外加非相干泵浦场或者两上能级间的粒子数的衰减,也能实现LWI.然而,在产生LWI的区域中,SGC效应并非永远对产生LWI作正的贡献,在某些区域SGC项甚至会削弱LWI 的产生.本文给出了产生LWI的条件,并讨论了一类新型的量子相干效应.     

强磁场中氢原子自离化态的能级及宽度

使用Bsplines与复坐标旋转相结合的方法计算了均匀外磁场(2.35×10~6≤B≤1.175×10~4T)中氢原子│m│=0—5,偶宇称和奇宇称自离化态的能级和宽度.并与已有的结果作了比较.分析了共振态能级位置和宽度与态的宇称、磁量子数│m│及磁场强度的关系.结果表明:Bsplines与复坐标旋转方法相结合可以有效地用于强外场中原子自离化态的计算. 关键词：     

应用双光子共振非简并四波混频测量Ba原子里德伯态

使用具有中间态的双光子共振非简并四波混频(NFWM)测量了Ba原子J＝0和J＝2的偶宇称里德伯线系，与现代实验方法不同，本方法是纯光学的方法，其光路简单，检测的是相干光，而不是电子或离子信号.当用窄带宽的激光时，本技术对里德伯能级的窄光谱结构可以获得消多普勒的分辨率. 关键词： 四波混频 里德伯态     

非线性光学 非线性光散射、振荡与谐波产生

O437 2006032118应用双光子共振非简并四波混频测量Ba原子里德伯态=Observation of Rydberg series of neutral barium by two-photon resonent nondegenerate four-wave mixing[刊,中]/孙江(河北大学物理科学与技术学院.河北,保定(071002)) ,左占春…∥物理学报.—2006 ,55(1) .—221-225使用具有中间态的双光子共振非简并四波混频( NF-WM)测量了Ba原子J=0和J=2的偶宇称里德伯线系。与现代实验方法不同,本方法是纯光学的方法,其光路简单,检测的是相干光,而不是电子或离子信号。当用窄带宽的激光时,本技术对里德伯能级的窄光谱结构可以…     

同向电场磁场中氢原子的能级分裂

用通用软件Mathematica和简并微扰论计算了氢原子n=3~7能态在一对同方向电磁场中的能级分裂(不考虑自旋).数值结果表明:在许多情况下,一级修正可以使能级简并完全解除,这时总体能级分裂不是等间距的;但在一定条件下,总体能级分裂是等间距的,此时能级简并不能完全解除,只分裂为3n-2个不同能级.现有文章的结论是欠周全的.     

Sm原子奇宇称Rydberg态光谱

结合共振激发和场电离探测技术,通过总角动量量子数0→1→0→1的激发路径,研究了第一电离阈附近的Sm原子奇宇称Rydberg态4f~66snp(J=1)。首先,在45 200～45 500 cm~(-1)能量范围内共发现了94个奇宇称Rydberg能级。其次,通过对有效量子数和Rydberg能级结构特点的分析,将其中68个能级归属为3个束缚Rydberg系列,另外26个能级也给出了能级位置。然后,利用Rydberg-Ritz公式,对3个Rydberg系列分别进行了拟合,获得了Sm原子的电离阈为(45 519.61±0.79) cm~(-1)。最后,采用6种偏振组合激发,由偏振选择定则,进一步验证了这些奇宇称Rydberg态总角动量量子数为1。这些结果首次证实了场电离探测技术对Sm原子高激发Rydberg态的适用性,并且通过对奇宇称Rydberg系列拟合得到的Sm原子电离阈与文献中通过偶宇称Rydberg系列获得的值(45 519.64±1.39) cm~(-1)基本一致。     

氢原子能级简并度与对称性的关系

1 能级简并与对称性关系的一般讨论 用量子力学处理实际问题时,体系各能级的简并度(或权重)是极为重要的.如何判断一个体系的能级是否简并,量子力学中有一条定理[1]:     

Lipkin-Meshkov-Glick模型中的能级劈裂与宇称振荡研究

Lipkin-Meshkov-Glick (LMG)模型原本描述的是核物理系统,然而近年来,人们发现它广泛存在于凝聚态物理、量子信息、量子光学中,因此对其研究兴趣正在升温.本文采用精确对角化的方法以及量子微扰理论计算和分析了LMG模型在费米子数量为有限N时的能谱结构.在U(1)极限下给出它的能级精确解,发现其相互交错成渔网结构.而离开U(1)极限,系统的能级总是奇偶宇称成对地分组,形成束缚态,并且宇称会发生振荡,给出了宇称交叉点的临界塞曼场的位置.而达到Z2极限,系统能级则在零塞曼场附近形成劈裂,解析地计算了这些能隙与塞曼场之间关系,并发现对于奇数和偶数的N,各能态宇称的行为有所差别,具体而言,奇数N系统各态在零塞曼场处会发生宇称改变,而偶数N不会.     

Ac vortex-dependent torsional oscillation response and onset temperature T0 in solid 4He

Detailed studies of ac velocity V_{ac} and T dependence of torsional oscillator responses of solid 4He are reported. A characteristic onset temperature T_{0} approximately 0.5 K is found, below which a significant V_{ac}-dependent change occurs in the energy dissipation for the samples at approximately 32 bar and for one at 49 bar. A V_{ac} dependence of the so-called "nonclassical rotational inertia" fraction also appears below approximately T_{0}. The log(V_{ac}) linear dependence, which suggests involvement of quantized vorticies, was examined in the nonclassical rotational inertia fraction. We find a common 1/T;{2} dependence for this linear slope change in all of the samples for 30相似文献   

Bound states of the Klein－Gordon and Dirac equations for potential V0tanh2(r/d)

The exact bound state wavefunctions and energy equations of Klein－Gordon and Dirac equations are given with equal scalar and vector potential s(r)=v(r)=V(r)/2=V_0tanh^2(r/d). The relation between the energy equation and that of relativistic harmonic is discussed.     

谐振子的角动量

对三维以内的谐振子的宇称进行分析,并由宇称守恒出发,根据同一能级的简并度相同,导出谐子角动量的可能值。     

Positive parity low spin states of odd-mass tellurium isotopes

In this work, we analyse the positive parity of states of odd-mass nucleus within the framework of interacting boson fermion model. The result of an IBFM-1 multilevel calculation with the lg_9/2, 2d_5/2, 2d_3/2, 3s_1/2 and one level, 1h_11/2 with negative parity, single particle orbits is reported for the positive parity states of the odd mass nucleus ^123-125Te. Also, an IBM-1 calculation is presented for the low-lying states in the even-even ^124-126Te core nucleus. The energy levels and B (E2) transition probabilities were calculated and compared with the experimental data. It was found that the calculated positive parity low spin state energy spectra of the odd-mass ^123-125Te isotopes agree quite well with the experimental data.     

Lattice QCD Towards Nuclear Forces

Recent studies of nuclear forces based on lattice QCD are presented. Not only the central potential but also the tensor potential is deduced from the Nambu?CBethe?CSalpeter wave function measured with lattice QCD. This method is applied to various kinds of nuclear potentials, such as ${V_{NN}, V_{\Lambda N}, V_{p{\Xi}^0},V_{\Lambda\Lambda-N\Xi-\Sigma\Sigma}}$ (coupled-channel potential), and ${V^{\{{\bf {27},{8}_s,{1},{10},\overline{10},{8}_a}\}}}$ (flavor representation potential). The energy dependence and the angular momentum dependence of the quenched V _NN is studied. A challenge for three-nucleon force from lattice QCD is also presented.     

利用磁谱仪测量90Sr-90Y放射源的β衰变能谱

利用近代物理实验中的磁谱仪测量了90Sr～90Y放射源的β衰变能谱．得到的能谱和普遍的口衰变能谱相似;得到的口射线最大能量与平均能量比值和文献中给出的一些放射源的比值接近,这些都说明了该实验测量数据的可靠性．运用库里厄（Kurie）图,研究了此放射源的β衰变能谱,得到的跃迁性质和能级自旋宇称与此放射源已有的数据相吻合,说明在近代物理实验中能够利用磁谱仪测量原子核的β衰变能谱、研究原子核的跃迁性质和能级自旋宇称．     

Experimental test of the high-frequency quantum shot noise theory in a quantum point contact

We report on direct measurements of the electronic shot noise of a quantum point contact at frequencies nu in the range 4-8 GHz. The very small energy scale used ensures energy independent transmissions of the few transmitted electronic modes and their accurate knowledge. Both the thermal energy and the quantum point contact drain-source voltage V_{ds} are comparable to the photon energy hnu leading to observation of the shot noise suppression when V_{ds}相似文献   

Excitation of even triplet levels of YII in the e-Y collisions

The excitation of high-lying triplet levels of a singly charged yttrium ion by electron-atom collisions is studied experimentally. The parity of the levels studied coincides with the parity of the initial state YI. Forty one excitation cross sections with simultaneous single ionization are measured for an exciting electron energy of 50 eV. The optical excitation functions (OEF) are recorded for the majority of transitions in the electron energy range 0–200 eV. The total cross sections are determined for 20 energy levels. Possible channels of a simultaneous excitation-ionization process are discussed.     

Sn同位素的能级密度和熵

能级密度在研究核物理的动力学、热力学性质中具有重要的物理意义。本文利用壳模型和截断算法计算了Sn同位素的最低10 000个状态。$^{116}{\rm{Sn}}$在Sn同位素中空穴数和粒子数都为8,能级最为复杂,根据$^{116}{\rm{Sn}}$能级密度研究了能级密度与角动量的关系和体系的微正则熵。研究发现在偶宇称时的最低平均能级出现明显的角动量奇偶效应,用泡利不相容原理得到合理解释。进一步,又研究了Sn同位素的此性质,得到相同的结论。$^{116}{\rm{Sn}}$的微规范熵在低能量段受奇宇称的波动,这与中子对的断裂有关。     

Remnants of a Bronze Age Rampart in Upper Bavaria: A Mössbauer Study

The remains of a Bronze age rampart found near Bernstorf, above the Amper valley some 30 km north of Munich in Upper Bavaria, were studied by Mössbauer spectroscopy and X-ray diffraction (XRD). The properties of the finds confirm the assumption that the rampart was destroyed by a fire, which caused much of the material to reach temperatures well above 1000°C. The results demonstrate the usefulness of Mössbauer sepctroscopy and XRD in studies of materials heated in disastrous fires.