类氢O、N离子入射Al表面俘获电子布居几率的理论与实验研究

利用“二态矢量模型”详细研究了高电荷态O⁷⁺,N⁶⁺离子入射Al表面时中间里德伯态的形成过程,给出了电子被俘获至不同量子数(n A=2-7)的几率,以及电子俘获至里德伯态最可能的离子-表面距离.计算结果表明,较大的主量子数nA对应较小的里德伯态几率,因此O⁷⁺,N⁶⁺离子入射Al表面时辐射的X射线主要来源于较小的n A至基态的退激.为了验证计算结果,测量了O⁷⁺,N⁶⁺离子入射Al表面的X射线发射谱,并运用FAC程序计算了不同高里德伯态退激到基态的跃迁能(np–1s).实验测量到O,N的K-X射线峰,其特征峰的中心值接近主量子数n=2至n=1的跃迁能,说明发射的X射线主要来源于2p–1s的跃迁,与“二态矢量模型”理论计算的几率一致.     

通过cluster态实现两粒子纠缠态的量子几率隐形传态

提出通过一个四粒子cluster非最大纠缠态作为量子信道来实现一未知两粒子纠缠态的量子几率隐形传态方案。在此方案中,纠缠态可以实现一定的几率传输,此几率由cluster态中绝对值较小的两个系数决定。如果我们用cluster最大纠缠态作为量子信道,此时几率隐形传态就成了一般的隐形传态,即成功传输的几率为100%。     

干涉项对e~+e~-→q+ng两种色连接几率的影响

传统高能e+ e-→hadrons事例产生器普遍采用大Nc 近似 ,使色单态链产生几率达到 10 0 %而色分离态几率为 0 .本文在Nc=3的真实情况下 ,研究了干涉项中颜色部分和动量部分的来源及性质后发现 ,对e+ e-→qq +ng部分子末态中胶子数 2 ,3,干涉项使色单态链产生几率进一步下降到 6 7% ,5 8% ,而n =2时的色分离态几率则增大至不考虑干涉项的 2倍 .由上推断当胶子数n更大时色单态链几率将远小于 1,色分离态几率将更显著增加     

干涉项对e+e－→qq+ng两种色连接几率的影响

传统高能e⁺e^－→hadrons事例产生器普遍采用大N_c近似,使色单态链产生几率达到100%而色分离态几率为0.本文在Nc=3的真实情况下,研究了干涉项中颜色部分和动量部分的来源及性质后发现,对e⁺e^－→qq+ng部分子末态中胶子数2,3,干涉项使色单态链产生几率进一步下降到67%,58%,而n=2时的色分离态几率则增大至不考虑干涉项的2倍.由上推断当胶子数n更大时色单态链几率将远小于1,色分离态几率将更显著增加.     

Cu(100)表面上H2/D2散射的六维态-态量子动力学研究：位点平均模型的有效性

基于由optPBE-vdW密度泛函计算的数千个数据点拟合得到的精确的神经网络势能面,本文采用含时波包方法对H₂/D₂在刚性Cu(100)表面上的态-态散射进行了六维量子动力学计算. 与以往的理论和实验比较了H₂和D₂在Cu(100)中的振转(非)弹性散射的结果. 特别是通过将六维的(非)弹性散射几率与从十五个位点加权平均四维几率的结果比较,测试了在该体系中位点平均近似模型的有效性. 具体来说,位点平均模型很好地重现了振动弹性散射几率,尽管对于高能下的振动非弹性散射结果没那么好. 结果说明在未来研究重双原子或多原子分子从金属表面的态-态散射动力学时,可以使用位点平均模型来降低全维计算过高的成本.     

向量子通信迈出了一大步

量子通信是基于量子力学的非定域效应 .一对粒子处于某种量子力学纠缠态 ,其波函数可以表示为ψ(A ,B)〉=12 (〉A 〉B- 〉A 〉B) ,这里〉A 代表粒子A的自旋“向上” ,以此类推 .单独看粒子A ,它的自旋或的几率各占 5 0 % ;单独看粒子B ,情况也如此 .然而 ,一旦进     

稀土区奇奇核πh_(11/2)νi_(13/2)带B(M1)/B(E2)比值增强特性

在稀土区奇奇核πh11/2νi13/2转动带中,系统地观测到随转动频率或角动量增加,B(M1)/B(E2)曲线表现出所谓parabola like形状,即在增加到某一转动频率或自旋后,B(M1)/B(E2)比值快速增强。基于推转模型和粒子转子模型关于奇奇核二准粒子转动带磁偶极约化跃迁几率的描述,对稀土区双奇核的这一行为进行了讨论。指出该现象的发生与νi13/2准中子转动顺排特性密切相关。B(M1)/B(E2)比值在接近第二带交叉(即BC准中子对顺排)的较高频率处的增强效果,可以理解为主要来源于带交叉引起的波函数中混合四准粒子成分的结果。通过对B(M1)/B(E2)比值的增强效果发生在较低频率处的分析,对稀土区奇奇核πh11/2νi13/2带角动量耦合图像有了进一步认识。     

三粒子GHZ态的量子信息分离方案(英文)

提出一个用GHZ态作为量子信道分离类GHZ态的方案.如果发送者Alice预先知道原量子态,Alice执行两量子比特投影测量后,接收者Bob和Charlie一起合作能恢复初态.我们计算了这个方案成功的几率和消耗的经典信息.一般地,Alice能成功地分离量子态的几率是1/4和消耗的经典信息是3/4经典比特.然而,在五种特殊情形下,消耗一些多余经典信息后,成功的几率能达到1/2甚至1.     

两态模型中的振动态布居转移

以氢化锂极性双原子分子为例,运用含时量子波包法数值求解两态模型,从理论方面研究了基电子态X¹Σ⁺通过跃迁偶极矩到激发电子态A¹Σ⁺,两态模型中的振动态布居转移过程.基电子态上以及激发电子态上各自的振动态通过激光脉冲与永久偶极矩作用完成布居转移过程也考虑在内.在紫外光和红外光区域内,使用短的线性偏振激光脉冲实现了高效的布居转移.经过选择激光脉冲的峰值强度、中心频率以及持续时间等参数,在激光脉冲关闭后,最终的布居转移几率都超过了90%.     

类镁离子3s2 1S0-3s3p 3P1(Z=14～103)跃迁的相对论多组态研究

利用全相对论性多组态Dirac-Fock平均能级(MCDF-AL)方法系统计算了高剥离类镁离子互组合线3s2 1S0-3s3p 3P1(Z=14～103)光谱跃迁的能级间隔和跃迁几率.计算中考虑了重要核的有限体积效应及Breit修正和QED修正,所得结果和最近的实验数据及理论计算值进行了比较.结果表明,高原子序数的高荷电离子跃迁的互组合线跃迁几率和中性原子的电偶极E1的相当.在ICF和MCF高温高密度激光等离子体中,互组合线跃迁几率过程不容被忽视.     

Scission configuration in quaternary fission

Trajectory calculations have been carried out to obtain information about scission configuration in quaternary fission on the basis of observed angular-correlation and energy correlations between two alpha particles in the spontaneous quaternary fission of²⁵²Cf. A number of plausible hypotheses for the scission configuration were tested against the experimental observations on the two alpha particles. The role of mutual repulsion between two alpha particles at scission in deciding the final energy angular correlations has been examined. It was found that only one hypothesis regarding scission configuration is consistent with the experimental data.     

The complex trajectory method and dissipation in fission

The sensitivity of the muon attachment probabilities to the light fragments of prompt fission W _l on the fission dynamics is discussed. It is shown that the final W _l value consists of two contributions: one from the point of scission and a second from avoided crossing of the levels. The relative contribution from the prescission phase turns out to be higher for more asymmetric fission.     

Neutron transfer reactions with very heavy ions

We have studied neutron transfer reactions induced by ¹³²Xe on three rare-earth targets at $\text{E}\text{V}{}_{\mathrm{C}}\text{～ 1.1}$. By using particle-particle-γ coincidence techniques we were able to identify final products and states populated in the one- and two-neutron reactions.The dependence of the transfer probabilities on the distance of closest approach is discussed in terms of effective penetration factors. The results seem to indicate the importance in two-neutron transfer of intermediate states with ? 6 MeV of excitation energy. The effect of excitation energy on the enhancement of the two-neutron transfer is discussed. A qualitative interpretation of the spin dependence of the one-neutron γ-ray yields in terms of the spatial localization of the wave functions involved is given.     

Gauging a quantum heat bath with dissipative Landau-Zener transitions

We calculate the exact Landau-Zener transition probabilities for a qubit with an arbitrary linear coupling to a bath at zero temperature. The final quantum state exhibits a peculiar entanglement between the qubit and the bath. In the special case of diagonal coupling, the bath does not influence the transition probability, whatever the speed of the Landau-Zener sweep. It is proposed to use Landau-Zener transitions to determine both the reorganization energy and the integrated spectral density of the bath. Possible applications include circuit QED and molecular nanomagnets.     

Lifetime measurements in chiral nucleus 130Cs

The level lifetimes in partner bands of 130Cs have been measured using the Doppler Shift Attenuation method. The high-spin states of 130Cs were populated via fusion evaporation reaction 124Sn(11B,5n)130Cs at a beam energy of 65 MeV. The absolute M1 and E2 transition probabilities have been deduced. The results indicate that the partner bands of 130Cs manifest the chiral properties.     

A SUGGESTIVE WAY OF DERIVING THE QUANTUM PROBABILITY RULE

The familiar modulus squared form of all quantum mechanical probabilities is derived from an assumption of equal a priori probabilities concerning the final states available.     

Transition to fixed final states in two-photon photoemission from adsorbate–metal systems

A simple theory is presented to study the final state transition in the two-photon photoemission (2PPE) processes of the adsorbate on a metal surface, in the light of recent experimental observation for benzene/Cu(1 1 1) system. The 2PPE spectrum is calculated for a model system assuming that an unoccupied adsorbate level above the vacuum, populated by the two-photon excitation, couples to a continuum of free photoelectrons. An analysis of the 2PPE spectra as a function of the incident photon energy reveals the spectral features including the possibility of Fano-type modification and resonance enhancement of the final state transition in the 2PPE processes. Attempt is also made to explain why the d-band emission of the substrate is enhanced in the presence of adsorbates.     

Toward optimizing stream fusion in multistream recognition of speech

A multistream phoneme recognition framework is proposed based on forming streams from different spectrotemporal modulations of speech. Phoneme posterior probabilities were estimated from each stream separately and combined at the output level. A statistical model of the final estimated posterior probabilities is used to characterize the system performance. During the operation, the best fusion architecture is chosen automatically to maximize the similarity of output statistics to clean condition. Results on phoneme recognition from noisy speech indicate the effectiveness of the proposed method.     

Intergalactic obscuring matter and holes between cluster structures of galaxies

Summary The location of individual intergalactic dark clouds, as well as the search for obscuring matter in some scantly populated areas between clustering structures so far has led to no final conclusion. In several cases, however, arguments can be set forth in favour of the thesis that some dark clouds are located in regions of space scantly populated with galaxies. Paper presented at the Congress “Galactic and Extragalactic Dark Matter”, Roma, 28 to 30 June 1983.     

In the exit channel of nuclear fission

The final period of nuclear fission is discussed. We propose the following picture: Nuclear scission happens because of an hydrodynamic instability triggered by random surface vibrations. Thus the scissioning complex ruptures at random positions. Measured total kinetic energies point to the very relevance of the instability, while the randomness of rupture shows up in neutron emission data.