Σ-原子能级的理论计算与分析

通过对Σ-原子的理论分析,数值求解了相应的Dirac方程,得到 了一组Σ-原子的能级值,与实验数据相当吻合;其结果连同K-原子的情况支持了Batty 光学模型势在奇异原子中应用的正确性,进而表明核子间的强相互作用力为吸引力.     

K-原子能移和宽度的唯象分析

尝试用Woods-Saxon形式的光学势来分析K原子，通过拟合一系列K原子数据，得到了一套最佳光学势参数. 把得到的这套光学势和前人的其它几种光学势在接近核表面处作了比较，发现他们彼此符合得很好. 另外，与核子-核势相比较，对于虚部势，K-核的Woods-Saxon势与核子-核的很相似，但是对于实部，K-核势要更深更窄一些.     

P原子的光学模型势与核极化修正

基于SIC-X_α的较为严格的计算方法,对于Rydberg电子态的交换参数采用自洽场模型计算核极化,结果比文献[15[的计算方法要精确.另外文献[15]在计算P²³⁸U的能级跃迁时,模型还不够完善,存在着难以克服的弊端,计算结果也不可能准确.20世纪70年代初,Batty就进行强相互作用势模型的研究,经过二十几次不断探索与改进,在1997—2000年给出了光学模型势的正确形式.对Rydberg电子态的交换参数采用自洽场模型计算核极化,用以修正Batty光学模型势下的P²³⁸U能级跃迁,得到反质子原子的相应能级.结果与实验数据相当符合.连同π^-,K^-,∑^-,Ξ^-原子的情况支持了Batty光学模型势在描写核子间强相互作用的正确性,同时也表明计算核极化的方法是正确的,为反粒子原子及奇特原子的深入研究及应用提供了理论依据.     

K■强相互作用束缚态及K~ K~-原子态的研究

讨论了K■的强相互作用单介子交换势,发现当考虑动量平方项时,仅由单介子(ρ,ω,φ)交换势, 不足以构成束缚态．K K-在库仑势的作用下可以形成束缚态,我们进一步计算了单介子交换势对 K K-库仑势束缚态能级的影响以及K K-束缚态衰变到ππ和ηπ的宽度．     

相对论微观光学势中相互作用力程的效应

从关于相对论的核子-介子场理论的Walecka模型出发,利用由Walecka模型得到的二核子的相互作用势,对定域密度近似下的光学势进行折叠,来考虑相互作用力程在核——有限核的相对论微观光学势中的效应,并用所得到的光学势分析核子与有关核的弹性散射微分截面和有关自旋可观测量,与定域密度近似计算相比,本文的计算结果同实验值有更好的符合.     

中能重离子碰撞中K介子产生动力学研究(英文)

基于兰州量子分子动力学(LQMD)模型研究了阈能附近K介子(K0和K+)产生动力学机制。LQMD模型能够较好地描述中能重离子碰撞中K介子产额分布。通过拟合K介子动能谱分布,计算中采用了排斥的K-核子相互作用势。该光学势增强了高动量K介子产生,而降低了K介子总产额。结合实验数据比较,在高密区域给出了较软的对称核物质状态方程。对称能的软硬对K0/K+比值起着重要作用,特别是在阈下区域。而K介子光学势对K0/K+比值激发函数影响不明显。     

势函数对强激光辐照下原子高次谐波辐射的影响

理论上研究了中红外强激光分别与长程库仑原子和短程势模型原子相互作用产生的高次谐波辐射.发现在相同激光参数条件下,与长程库仑原子的谐波辐射相比,短程原子具有更低的辐射效率,但在高频区域(接近cutoff位置),二者效率相似.通过对谐波辐射的时间频率分析发现,在短程模型原子谐波辐射中,长轨道发挥更重要的作用.利用其产生的高次谐波辐射,可以产生孤立阿秒脉冲.     

光学腔与原子强耦合的实验研究进展

光学腔与原子强耦合系统是量子物理研究的基本系统,不但具有重要的物理意义,而且为量子信息、量子计算和量子精密测量中关键技术的产生和关键器件的研发提供了理想系统。强耦合腔与原子相互作用实验从20世纪90年代开始发展,经过多年的研究,在单原子与光学腔强耦合和原子系综与光学腔的耦合研究方面取得了重大进展。随着多原子阵列量子操控技术的进步,可控的多原子阵列与光学微腔强耦合系统近年来成为腔量子电动力学的重要研究方向。然而,目前实现确定性可控的多原子阵列与腔的强耦合仍面临巨大的技术挑战,可控原子数还停留在两个。简要回顾了近年来光频区强耦合腔量子电动力学系统在上述方面的主要实验进展和相应的实验方案,并展望了未来的发展。     

强耦合腔-QED系统中原子的纳秒脉冲激发光谱研究

本文在多原子强耦合腔-QED系统中,利用脉冲宽度为5 ns的强脉冲光在垂直于腔轴方向直接激发原子,脉冲的峰值功率为40 mW,通过光学腔观测激发原子辐射到腔中的光子获得相应的激发光谱。我们发现当光场频率和原子跃迁失谐±80 MHz时原子激发率达到最大,而在共振时原子激发被抑制。我们建立了脉冲光与三能级原子相互作用的模型,通过缀饰态能够解释此现象。     

电子在中性原子势场中的自由—自由跃迁吸收截面的理论计算

本文采用等效势模型,并基于Hartree——Fock解析波函数和X_α数值波函数计算自由电子与中性Ar和Si原子的相互作用势。用直接计算矩阵元方法和通过计算碰撞相移方法计算了电子在中性Ar原子势场中的自由—自由跃迁吸收截面,所得结果与Ashkin理论计算值符合较好,对中性Si原子亦进行了计算。通过计算说明了等效势模型对计算中性原子的自由—自由跃迁吸收截面是成功的。     

一类环状非球谐振子势场中相对论粒子的束缚态解

提出了一种新的环状非球谐振子势, 在标量势与矢量势相等的条件下，给出了其Klein-Gordon方程和Dirac方程的束缚态解. Klein-Gordon方程的θ角向波函数以超几何函数表示，径向波函数可用合流超几何函数或广义拉盖尔多项式表示，能谱方程由径向波函数满足的束缚态边界条件得到. Dirac方程的旋量波函数可用Klein-Gordon方程的解构造. 关键词： 环状非球谐振子势 Klein-Gordon方程 Dirac方程 束缚态     

库仑势加新环形势的相对论束缚态

在标量势等于矢量势的条件下，获得了库仑势加新环形势的Klein-Gordon方程和Dirac方程的束缚态的精确解. 对于Klein-Gordon方程，获得了精确的能谱方程和归一化的波函数. 对于Dirac方程，给出了精确的能谱方程和归一化的旋量波函数. 关键词： 库仑势加新环形势 束缚态 精确解     

The acoustical Klein-Gordon equation: the wave-mechanical step and barrier potential functions

The transformed form of the Webster equation is investigated. Usually described as analogous to the Schr?dinger equation of quantum mechanics, it is noted that the second-order time dependency defines a Klein-Gordon problem. This "acoustical Klein-Gordon equation" is analyzed with particular reference to the acoustical properties of wave-mechanical potential functions, U(x), that give rise to geometry-dependent dispersions at rapid variations in tract cross section. Such dispersions are not elucidated by other one-dimensional--cylindrical or conical--duct models. Since Sturm-Liouville analysis is not appropriate for inhomogeneous boundary conditions, the exact solution of the Klein-Gordon equation is achieved through a Green's-function methodology referring to the transfer matrix of an arbitrary string of square potential functions, including a square barrier equivalent to a radiation impedance. The general conclusion of the paper is that, in the absence of precise knowledge of initial conditions on the area function, any given potential function will map to a multiplicity of area functions of identical relative resonance characteristics. Since the potential function maps uniquely to the acoustical output, it is suggested that the one-dimensional wave physics is both most accurately and most compactly described within the Klein-Gordon framework.     

On Internucleon Interaction of Composite Nucleon

We discuss the low energy nucleon-nucleon interaction leading to a bound state, namely the deuteron problem. The currently known method of calculating internucleon interactions is the boson exchange potential model, where the Klein-Gordon equation for a virtual pseudoscalar boson with a single point-like nucleon source is solved using the Green function method. This method is known to be inadequate in particular to the internucleon problem leading to a bound state. As an alternative we propose to solve internucleon potential problems, including the bound state, by solving the Klein-Gordon equation in which the interaction term has been introduced in a more invariant way. In the place of the single source term used in the standard method the interaction term is introduced in the covariant derivative form in the spirit of the minimum coupling scheme. It turns out that this method is not only mathematically satisfactory (gauge and Lorentz invariant formalism aspect), but also gives a more physically satisfactory interpretation of the internucleon interaction mechanism. For a deuteron bound state problem can then be solved approximately using the variational calculus. We obtain the analytic expression for the internucleon potential as a function of internucleon distances. The minimum energy value 2,2 MeV, the binding energy of the deuteron, is found to be at equilibrium distance of r_ab = ?_φ = 2 × 10^?13 cm.     

具有P?schl-Teller型标量势与矢量势的Klein-Gordon方程和Dirac方程的束缚态

给出了具P?schl-Teller型标量势与矢量势的Klein-Gordon方程和Dirac方程的s波束缚态解. 关键词： P?schl-Teller势 Klein-Gordon方程 Dirac方程 束缚态     

Chiral dynamics of deeply bound pionic atoms

We present and discuss a systematic calculation, based on two-loop chiral perturbation theory, of the pion-nuclear s-wave optical potential. A proper treatment of the explicit energy dependence of the off-shell pion self-energy together with (electromagnetic) gauge invariance of the Klein-Gordon equation turns out to be crucial. Accurate data for the binding energies and widths of the 1s and 2p levels in pionic 205Pb and 207Pb are well reproduced without need for a notorious "missing repulsion" in the pion-nuclear s-wave optical potential. The connection with the in-medium change of the pion decay constant is clarified.     

Quark potentials for mesons in the Klein-Gordon equation

Two relativistic potential models are applied to describe meson spectroscopy in a unified way, encompassing both light and heavy quark systems. A combination of linear and coulomb potentials has been investigated for Klein-Gordon equation using the WKB approximation. A power-like phenomenological potential model has also been studied in the Klein-Gordon framework. Meson masses calculated for both the potentials give a good agreement with the corresponding experimental values.     

Causal interpretation of the modified Klein-Gordon equation

A consistent causal interpretation of the Klein-Gordon equation treated as a field equation has been developed, and leads to a model of entities described by the Klein-Gordon equation, i.e., spinless, massive bosons, as objectively existing fields. The question arises, however, as to whether a causal interpretation based on a particle ontology of the Klein-Gordon equation is also possible. Our purpose in this article will be to indicate, by making what we believe is a best possible attempt at developing a particle interpretation of the Klein-Gordon equation, that such an interpretation is untenable. To resolve the nonpositive-definite probability density difficulties with the Klein-Gordon equation, we modify this equation by the introduction of an evolution parameter. We base our subsequent considerations on this modified Klein-Gordon equation. Partly to motivate the need for a relativistic causal interpretation and partly to give emphasis to aspects of the causal interpretation often overlooked, we begin our article with a brief historical survey of the causal interpretation.Other work commitments prevented publication of this article in the special issue ofFoundations of Physics in honor of Prof. J. P. Vigier. I would nevertheless like to dedicate this work to Prof. Vigier in recognition of this untiring contributions to the causal interpretation in particular and to the foundations of physics in general. I take this opportunity to thank Prof. Vigier for his help during my Royal Society fellowship spent at the Institut Henri Poincaré in the academic year 1988–1989.     

一维Hulthén势场中Klein-Gordon粒子的透射共振

用Heaviside函数构造出一维对称的Hulthén势垒,求解了其满足的Klein-Gordon方程. 散射态的精确解可以由超几何函数表示, 透射系数T和反射系数R能由Klein-Gordon 方程满足的边界条件得到.并由流密度守恒推导出低动量粒子发生透射共振的条件. 关键词： Klein-Gordon方程 Hulthén势垒 散射态 透射共振     

具有线性型标量势和矢量势的Klein-Gordon的束缚态

给出了当线性型标量势大于或等于其矢量势时的Klein-Gordon方程的s波束缚态解，其解可 用合流超几何函数表示. 关键词： 线性势 Klein-Gordon方程 束缚态