激光场中正电子对反质子的辐射复合反应

在软光子近似下, 计算了激光场中正电子对反质子的辐射复合过程. 辐射场作为经典场处理, 入射正电子态用Coulomb-Volkov波函数描述, 末道形成的反氢缀饰态由含时间微扰论给出. 理论结果显示激光背景明显削弱了反氢生成截面.     

激光场中电子碰撞氢原子电离三重微分截面

本文用CPB(Coulomb-Projected Born)近似和GCPB(Generalised Coulomb-Projected Born)近似对激光场中电子与氢原子碰撞电离的三重微分截面及平均吸收或发射光子数进行了计算,并将结果与P.Cavaliers等(1980)的Born近似结果进行了比较。     

新激光技术生成冷电子偶素

美国的物理学家发现电子偶素（一种短寿命的电子与正电子的束缚态）可以通过用激光束照射硅的表面而生成.由于这种技术是高度可控的,并且适用于很宽的温度范围,因而对于为寻找物质与反物质特性上的微小差别而设计的低温实验是极为有用的.     

用玻尔理论统-处理氢原子、电子偶素和氦原子基态能级

用玻尔氢原子理论处理氢原子和电子偶素基态的方法，在假定了氦原子基态的经典模型后，给出了氦原子基态能级和半径，并与实验和量子力学变分法计算的结果作比较，说明玻尔氢原子理论对氦原子基态能级的计算有一定的意义．     

氧分子对电子偶素的态转换

把气凝硅胶作为可变能量的电子偶素源,用时间选择γ能谱仪研究电子偶素在氧气中的运动,验证快速电子偶素与氧分子非弹性碰撞发生的态的转换效应,测得在两个阈能附近的截面为2.1×10^－17cm²和6.6×10^－18cm².研究慢速电子偶素与氧分子弹性碰撞交换电子所致态转换,发现过程的截面与电子偶素平均速度的平方根成反比,这一过程可以提供比较干净的仲态电子偶素源进行其它精密物理实验.     

激光场中电子与氢原子的散射：Ⅱ.低频近似下的计算

本文在多重散射理论的框架下,研究了低频激光场中电子与氢原子的散射。计算了激光场中电子与基态氢原子弹性散射的微分截面,讨论了微分截面随光子数、散射角以及入射电子能量的变化规律,并与别人的结果作了比较。     

用玻尔理论统一处理氢原子、电子偶素和氦原子基态能级

用玻尔氢原子理论处理氢原子和电子偶素基态的方法,在假定了氦原子基态的经典模型后,给出了氦原子基态能级和半径,并与实验和量子力学变分法计算的结果作比较,说明玻尔氢原子理论对氦原子基态能级的计算有一定的意义.     

激光场中正电子对氢原子的电离反应

本文在一级Bom近似下，研究了激光场中正电子对基态氢原子的碰撞电离反应，并与入射粒子为电子的（e，2e）反应进行了对比．激光场中正电子态和敲出电子态分别采用Volkov波函数和Coulomb-Volkov波函数，靶原子的缀饰波函数由含时微扰论给出．计算结果显示激光缀饰的三重电离截面明显依赖于入射粒子电荷符号．激光越强，二者差距越大．     

对“微波共振跃迁法测量电子偶素2~3S_1-2~3P_1精细结构”实验拟合公式的探讨

本文对Michigan大学S.Hatamian等人在“微波共振跃迁法测量电子偶素2~3S_1-2~3P_J精细结构”实验中所用拟合公式进行了审慎的分析和推证,修正了该公式的功率增宽项,并就Mainz大学R.Ley等人对该公式的批评作了评价。最后,采用新、旧拟合公式对Michigan组实验数据进行拟合并讨论其结果。     

激光辅助的电子对氢原子的自由-自由跃迁

在一级玻恩近似和软光子近似下 ,研究了激光场中电子对氢原子基态的自由 自由跃迁,并考虑入射电子对束缚电子的交换效应 .发现Kroll Watson截面求和规则在大角度遭到明显破坏. In the first Born approximation and the soft-photon approximation, the laser-assisted electron-atomic-hydrogen free-free transition is investigated with taking the exchange effect into acount. We find that the Kroll-Watson sum rule is significantly violated in the backward direction.     

Positronium Molecules: Their Existence,Formation and Annihilation

The theoretical bases for establishing the existence of four-body molecules are discussed. A review of the theory of positronium molecules (Ps₂) is presented. Special attention is given to the role of Ps₂ in understanding the structure of similar quantum mechanical systems created in molecular crystals and semiconductors.     

反氢和反原子

自从狄立预言反粒子的存在后，虽然人们已经找到了几乎每个粒子的反粒子，但几代物理学家苦苦寻找着由反粒子组成的以原子，１９９６年１月ＣＥＲＮ宣布制成反氢原子，打开了通向反物质世界的大门子，引起轰动，文章叙述这一重大发现的物理背景，报道了上述发现，并展望由此开辟的崭新领域。     

Antihydrogen production in a combined trap

In this paper we study the properties of a Paul trap with a superimposed magnetic field (combined trap) and discuss the possibility of using this trap to simultaneously store positrons and antiprotons to form antihydrogen.     

Positronium atom in an ionic crystal

The Sommerfeld-Welker model of a hydrogen atom in a spherical, impenetrable force cavity is used to calculate the basic properties of positronium in an ionic crystal. The basic properties of positronium (the lifetime against 2- and 3-annihilation, the count rate of 3 coincidences, and the magnetic-quenching parameter) are found as functions of the radius of the spherical force cavity.Translated from Izvestiya VUZ. Fizika, No. 7, pp. 71–75, July, 1970.     

Calculation of Positronium Formation Cross Sections in Positron-Mg Collision

Using the optical-model, we theoretically investigate the positronium （Ps） formation in e^＋-Mg collision from the positronium threshold to 60.0eV. A complex equivalent local polarization potential is obtained to describe the rearrangement process, which reproduces Ps formation cross section. We report the total Ps （n = 1 ＋ 2） formation cross sections and compare them with the experimental measurements and other theoretical results.     

Antihydrogen production within a Penning-Ioffe trap

Slow antihydrogen (H) is produced within a Penning trap that is located within a quadrupole Ioffe trap, the latter intended to ultimately confine extremely cold, ground-state H[over ] atoms. Observed H[over ] atoms in this configuration resolve a debate about whether positrons and antiprotons can be brought together to form atoms within the divergent magnetic fields of a quadrupole Ioffe trap. The number of detected H atoms actually increases when a 400 mK Ioffe trap is turned on.     

A Self-Consistent Model for Positronium Formation from Helium Atoms

The differential and total cross sections for electron capture by positrons from helium atoms are calculated using a first-order distorted wave theory satisfying the Coulomb boundary conditions. In this formalism, a parametric potential is used to describe the electron screening in a consistent and realistic manner. The present procedure is self-consistent because (a) it satisfies the correct boundary conditions and post–prior symmetry, and (b) the potential and the electron binding energies appearing in the transition amplitude are consistent with the wave functions describing the collision system. The results are compared with the other theories and with the available experimental measurements. At the considered range of collision energies, the results agree reasonably well with recent experiments and theories.     

Antiproton reflection by a solid surface

The AE?IS experiment (Antimatter Experiment: Gravity, Interferometry, Spectroscopy (Drobychev et al., 2007)), aims at directly measuring the gravitational acceleration g on a beam of cold antihydrogen ( $\overline{\rm H}$ ). After production, the $\overline{\rm H}$ atoms will be driven to fly horizontally with a velocity of a few 100 m/s for a path length of about 1 meter. The small deflection, few tens of μm, will be measured using two material gratings coupled to a position-sensitive detector working as a Moiré deflectometer similarly to what has been done with atoms (Oberthaler et al., Phys Rev A 54:3165, 1996). Details about the detection of the $\overline{\rm H}$ annihilation point at the end of the flight path with a position-sensitive microstrip detector and a silicon tracker system will be discussed.     

Antihydrogen and fundamental symmetries

The prospects for testing CPT invariance and the weak equivalence principle (WEP) for antimatter with spectroscopic measurements on antihydrogen are discussed. The potential precisions of these tests are compared with those from other measurements. “If there is negative electricity, why not negative gold, as yellow...as our own, with the same boiling point and identical spectrallines...” A. Schuster [1], 1898