引力理论的场方程与自由粒子运动方程的一般形式

由物质场和引力场的较为广泛的拉氏函数密度及其在(ε^mn,ξ^μ)变换下的不变性出发,导出了引力场方程和自由粒子运动方程的一般形式。它们有着较为广泛的适用性。已表明广义相对论、ECSK理论及R+R²+T²型有挠引力理论等均可作为特殊情况纳入这个体系之中。 关键词：     

McMillan Tc公式的解析推导(Ⅱ)——μ*≠0情形

本文把文献[1]的理论以及所得到的T_c公式推广到μ^*≠0情形,得到T_c=(2γ)/πω_log·(ω_log/ω_c)^{(μ*/(λ-μ*))}·exp{-(1+λ)/(λ-μ^*)}. Inγ=C=0.5772是Euler常数。 关键词：     

准抛物型多量子阱结构中光学二次谐波

研究在掺杂n-i-p-i的抛物多量子阱结构中,由于非简谐修正项所导致的子带间光学二次非线性响应(对应于x⁽²⁾),计算表明,x⁽²⁾比GaAs体材料高一至二个数量级,而其共振跃迁频率位于中红外区域。 关键词：     

有挠量子引力和无鬼de Sitter引力(Ⅰ)——线性协变规范下的有挠引力

本文在最一般的线性协变规范下计算了含有17个参数的有挠引力理论的传播子,发现拉氏函数中有三项对理论的粒子内容无影响。1^-粒子是规范有关的非物理粒子,与原始拉氏量是否无鬼、无快子没有关系。 关键词：     

非谐振子势的精确解和双波函数描述

求解了非谐振子势V(x)=x²/2+g/2x²的本征方程，给出了精确的能谱方程和归一化波函数.应用双波函数理论，得到了在非谐振子势场中单粒子运动状态的力学量的时间演化方程. 关键词：     

等温节流过程积耗散最小化

对一类普适传质规律等温节流过程进行了研究, 应用最优控制理论导出了对应于过程质量积耗散最小时最优性条件, 然后基于普适优化结果导出了传质规律[g∝(Δ p)^m]和线性传质规律[g∝Δ(μ)] 等各种特例下的优化结果, 并与熵产生最小、压力之比为常数和压力之差为常数等各种传质策略下的结果进行了比较, 给出了[g∝(Δp)^1/2], [g∝Δ(p)]和[g∝Δ(μ)] 等各种特例下的数值算例. 本文的研究结果对于实际节流过程 和设备的最优设计与运行具有一定的理论指导意义. 关键词： 等温节流 质量积耗散 最优控制 有限时间热力学     

标准模型中两类中性玻色子混合圈链图传播子的重整化及其e+e-→μ+μ-反应截面

采用电弱统一标准模型, 对光子γ和中间玻色子Z₀ 混合圈链图传播子的构架方式及其重整化问题作了详细分析与讨论, 并完成了有关解析计算, 获得了由参与电弱相互作用的各种混合圈构成的γ和Z₀的重整化链图传播子的解析计算结果. 此外, 我们还将此结果应用于高能物理中备受关注的一类轻子反应e⁺e^-→μ⁺μ^-中, 获得了在γ和Z₀所构架出的重整化混合圈链图传播中e⁺e^-→μ⁺μ^-反应截面的解析计算结果, 并将本文所获得的这一理论计算结果与实验观测值作了对比分析, 发现本文理论计算结果与实验观测值符合非常好, 并由此也获得了有关辐射修正的重要信息. 本文研究结果也可为探讨一般复杂传播子的理论研究与应用提供某些参考. 关键词： 标准模型 链图传播子 重整化 辐射修正     

d(x2-y2)+idxy混合波正常金属/绝缘层/超导体结中的隧道谱

考虑界面粗糙散射,在Blonder-Tinkham-Klapwijk(BTK)理论框架下,通过求解Bogoliubov-de-Gennes(BdG)方程,分别计算T=0K和有限温度下,d_(x²-y²)+id_xy混合波正常金属绝缘层超导体结中的准粒子输运系数和隧道谱.研究表明:隧道谱中的电导峰的劈裂程度强烈地依赖于d_xy波分量的强度、超导体的晶轴方位和界面粗糙强度,而温度的升高能压低电导峰. 关键词： NIS结 (x²-y²)+id_xy混合波超导体')" href="#">d_(x²-y²)+id_xy混合波超导体 隧道谱     

在Skyrme模型中关于解析质量计算的研究

本文用Reduce语言^[1]研究了Skyrme模型^[2、3、4]中孤立子质量的计算方法。上机计算结果表明,矩阵方法和具体展开方法比一般算符表达式更为优越。     

有激波的一维不定常气流的新的数值解法

解有激波的气体力学问题的数值解法,主要有特征线法和有限差分法两类。特征线法一般能给出高的精度,但当激波很弱、与特征线几乎平行时就需特殊处理^[1]。有限差分法的研究和发展更广,有人工粘性法^[2]、激波捕捉法^[8]、分离奇性法^[1]等处理激波的方案,它们又各有其特殊的技巧和问题。     

作用表示波动方程中与面有关项

这篇短文的内容是:(i)对於量子场论中的i(δψ[σ])/(δσ(x))=V(x,σ)ψ[σ] 如何由寻常的“曲面上的薛定谔方程”导出,作一个较严格的讨论,以及 (ii)讨论上式中的V(x,σ)在什么条件下不包含有σ。我们证明了所需的条件是 (?L^I)/(?φ_μ) (?L^I)/(?φ_ν)=(?²L)/(?φ_μ?φ_ν)F(φ,φ_ρ),式中L,L^I代表总拉格朗日及作用拉格朗日,φ代表场量,φ_μ代表φ/x^μ,F(φ,φ_ρ)代表φ及φ_μ的一个任意函数。     

The general three-vertex,BRS identities and renormalizability of the light-cone gauge

The general one-loop three-vertexГ _μeλ ^abc (p, q, r) in the four-component formulation of the Yang-Mills theory is calculated in the light-cone gauge. The nonvanishing counter Lagrangian constructed from this three-vertex and the self-energy is proportional to the original Lagrangian, the single renormalization constant being -11g² C _YM Г(2?ω)/48π². Gauge dependent and nonlocal counterterms do not contribute to the renormalization constant, but are needed to verify the appropriate Slavnov-Taylor (ST) and Becchi-Rouet-Stora (BRS) identities.     

Effective dielectric theory from QCD

New effective fields are defined in QCD by averaging the phase factor P exp∫_x0^x₀+?iA_μdx^μ in small four-dimensional boxes. Their effective lagrangian is constructed explicitly for G=SU(2). It is a version of the dielectric theory proposed by 't Hooft, Kogut and Susskind. The classical electric flux-tube solution is analyzed quantitatively.     

Magnetische Monopole und Quarks

We discuss the concept of Schwinger, which starts with the hypothesis of the existence of magnetical monopoles and results in a baryon model with magnetically charged constituents. Especially we analyse the mathematical consistency of such a theory. which admits a connection between some magnetically charged “quarks” and the homogeneous Maxwell-equations ?_v*F^μv(x^u) = 0, which, displaying a lack of symmetry with respect to the inhomogeneous one, ?_vF^μv(x^u) = 4?j^μ, are replaced by ?*j^μv. Here *j^μ(x^μ) means a conserved magnetic current which provides a monopole source for the magnetic field.     

Quantization of gauge-fields in the fock-schwinger gauge

The gauge conditionx _μ A ^μ =0 produces a theory which is free from Faddeev-Popov ghosts, but whose Green's functions obviously lack translational invariance. We present for the first time a consistent perturbation theory in this gauge. Besdes discussing example howlocal counter-terms in the action suffice for the one-loop renormalization ofS-matrix elements.     

Die EINSTEIN-Gruppe und die Symmetrie-Gruppen der Gravitationstheorie

The transformations x^?α = x^?α(x^β, g_μn?) in the function space of the g_μn?(x^λ) are corresponding to the coordinate transformations x^α = x^α(x^β) with some non-covariant conditions on the g_μn?(x^λ). Therefore, the transformations in the function space are corresponding to subgroups of the EINSTEIN group. The conditions for the g_μn? may be given in the space- time V₄ or on submanifolds (points, curves, surfaces and hypersurfaces) of the V₄. – A special case of the last problem is given by the CAUCHY conditions or by the DIRAC constraints for a special choice of the coordinates on a CAUCHY hypersurface x⁰ = 0. Then, the transformations x^?α = x^?α(x^l, g_rs, p^mn) in the phase space are EINSTEIN transformations preserving the synchronicity for x⁰ → 0.     

A theoretical and numerical evaluation of the steady-state burning rate of vertically oriented PMMA slabs

The steady state burning rate of vertically oriented slabs of poly-methyl-methacrylate (PMMA) is numerically investigated. Model predictions are compared with measurements and results of the laminar boundary layer (LBL) theory. The numerical model provides a solution of the Favre-averaged Navier–Stokes equations coupled with sub-models for turbulence, combustion, soot production and radiation. The modelling of condensed phase processes is based on the one-dimensional heat transfer equation and pyrolysis is treated as a phase change using the latent heat approach. Results show that the pyrolysing region can be divided into three regions. In the laminar part of the flow (Gr _x < 4.3 × 10⁷), the predicted normalised burning rate, [mdot]″ _p x/μ_∞, is a power-law function of Gr _x with an exponent close to that of the LBL theory, surface re-radiation being the primary source of discrepancies. From the LBL theory for free flow, it is demonstrated that the local burning rate is inversely proportional to the shear velocity gradient. This is globally confirmed by numerical model results. At Gr _x = 4.3 × 10⁷ the change in slope of the burning rate observed experimentally, which indicates the end of the laminar flow region, is reproduced numerically. From Gr _x = 2.5 × 10⁹ model results show that the surface mass flux of pyrolyzate increases with x, in agreement with experimental data in literature.     

Classical theory of a space-time sheet

By embedding the space-time V₄ in a higher-dimensional space M_N we can formulate a theory of gravity in which the true dynamical variables are the coordinates η^a(x) (a = 1,2,…, N) of V₄ with respect to M_N. Before constrained by the variational principle, which gives the equations of the four-surface V₄, all the coordinates η^a are independent. This enables the canonical formulation of the theory (without additional constraints except for the initial and boundary conditions on η^a and ones due to the reparametrization invariance) which is presented here. When expressed in terms of the metric tensor g_μ$\text{v}$ of the space-time four-surface V₄ the theory reduces to the Einstein general relativity.