普通物理力学和理论力学的整合

理顺物理类普通物理力学和理论力学的关系,将理论力学中的牛顿力学部分基本上都归入普物力学,加强分析力学部分,并增加非线性力学,改名为分析力学．     

给牛顿力学戴上相对论协变的光环,弊大于利

指出本刊一篇文章基本思路的不妥之处，简明扼要地阐明了牛顿力学和相对论力学的分界。     

On Classical and Quantum Objectivity

We propose a conceptual framework for understanding the relationship between observables and operators in mechanics. To do so, we introduce a postulate that establishes a correspondence between the objective properties permitting to identify physical states and the symmetry transformations that modify their gauge dependant properties. We show that the uncertainty principle results from a faithful—or equivariant—realization of this correspondence. It is a consequence of the proposed postulate that the quantum notion of objective physical states is not incomplete, but rather that the classical notion is overdetermined.     

创立量子力学的睿智才思(续2)——纪念矩阵力学和波动力学诞生80～81周年

1922年前后玻尔-索末菲的旧量子论在原子结构理论上取得辉煌成就的同时，它的致命弱点也开始暴露出来．反常塞曼效应是其一，原子光谱的多重线结构是其二，更不要说氢分子离子H2^＋问题了．一时多少杰出的物理学家为这些问题绞尽脑汁，设计了各种物理模型，提出一些“代用（德文Er-satz）”理论，诸如海森伯和泡利的Zwang之类，到头来还只得愁眉以对，一筹莫展．无怪乎海森伯把反常塞曼效应叫做“光谱项的动物学和塞曼植物学（Term Zoology and Zeeman Botany）”，意即在这个领域里物理学家只能像生物学家那样记录现象和描绘事实，提不出像样的理论．到1925年下半年，人们手里有了矩阵力学，问题是否可以解决了呢？万事俱备，只欠“东风”，那就是“自旋”．     

Classical Mechanics and Quantum Mechanics

The Newton equation of motion is derived from quantum mechanics.     

力学综合课程建设的研究和实践

简述了我校物理系进行力学综合课程建设的基本思想和措施，以及建立将普通物理力学、理论力学和量子力学基础综合成一门课程的新的教学内容结构体系的具体做法．这样做，不但大大减少了重复内容和课时。而且有助于学生从整体上把握力学理论的基本框架，有助于培养学生的综合研究能力和创新能力。     

量子理论的诞生和发展——从量子论到量子力学

简要叙述 ,从普朗克 190 0年首次对电磁波提出量子假设到狄拉克 192 8年对电子提出相对论性方程这段时间内 ,量子理论特别是量子力学诞生和发展的演化过程 .内容分黑体辐射和量子假设 ;老量子论的兴与衰 ;第一条通向量子力学的路———对应原理 ,包括矩阵力学 ,狄拉克的q -数 ;第二条通向量子力学的路———波粒二象性 ,波动力学 ;以及量子力学初步成长 (指 192 7年的表象理论、不确定关系、氦原子及氢分子和 192 8年的狄拉克相对性电子理论 )五个部分 .     

A Continuous Transition Between Quantum and Classical Mechanics. I

In spite of its popularity, it has not been possible to vindicate the conventional wisdom that classical mechanics is a limiting case of quantum mechanics. The purpose of the present paper is to offer an alternative formulation of mechanics which provides a continuous transition between quantum and classical mechanics via environment-induced decoherence.     

Particle Spin Described by Quantum Hamilton Equations

The anomalous Zeeman effect made it clear that charged particles like the electron possess a magnetic dipole moment. Classically, this could be understood if the charged particle possesses an eigenrotation, that is, spin. Within Nelson's stochastic mechanics, it was shown that the model of a rotating charged ball is able to reproduce the well-known spin expectation values. This classically motivated model of intrinsic rotation described in terms of a stochastic process is revisited here within the formalism of stochastic optimal control theory. Quantum Hamilton equations (QHE) for spinning particles are derived, which reduce to their classical counterpart in the zero quantum noise limit. These equations enable the calculation of the common spin expectation values without the use of the wave function. They also offer information on the orientation dynamics of the magnetic moment of charged particles beyond the behavior of the spin averages.     

Statistical basis for physical laws; non-relativistic theory

We extend the constructions of previous papers, showing the equivalence of quantum mechanics and a classical probability formalism with constraints assuring differentiable probability densities without contradictions, to show that these constructions also yield Maxwell's equations and the Lorentz force. These constructions have already yielded Schroedinger's equation for a charged particle in an electromagnetic field, but here it is shown that this statistical construction provides the basis for gauge conditions and defines a specific gauge for this non-relativistic formalism. These constructions also provide new insight into the relationship of Schroedinger quantum mechanics and a classical diffusion process.     

氢原子的固有电偶极矩

用经典力学和双波量子力学计算了氢原子的固有电偶极矩。双波量子理论算得的结果在经典极限下与经典力学的结果一致。普通量子力学对氢原子Stark效应中表现出来的电偶极矩难以做出很好的解释，因为一个波函数描述的是系综而不是单个粒子。经典力学和双波量子力学可描述单个粒子的行为，对永久电偶极矩的计算和解释显得自然而合理。     

再论牛顿力学形式和相对论力学的协变性

进一步论述了,将牛顿力学形式写成相对论协变形式的科学意义,同时指出了有关文章对这一观点所提出的异议是不妥的．     

A Continuous Transition Between Quantum and Classical Mechanics. II

Examples are worked out using a new equation proposed in the previous paper to show that it has new physical predictions for mesoscopic systems.     

On how the (1+1)-dimensional Dirac equation arises in classical physics

We demonstrate how the (1+1)-dimensional Dirac equation can be derived from the equation for the probability distribution governing a stochastic process when particles are permitted to propagate both backwards and forwards in time. This derivation uses a real transfer matrix and does not require a formal analytic continuation from classical physics. The physical significance of the quantity we interpret as being the wave function is discussed.     

Mechanical stress tensor for a fluid in a magnetostatic field

Summary Two constraints on the form of the mechanical stress tensor for an uncharged and linear dielectric fluid at rest in a magnetostatic field are determined. Moreover, it is shown that the stress tensor proposed by Helmholtz, that proposed by Einstein-Laub and that proposed by Liu-Müller are unacceptable as mechanical stress tensors for a dielectric fluid in the conditions stated above.     

Can the definition of mechanical stress tensor be applied to a dielectric fluid in an electrostatic or magnetostatic field?

Summary It is proved that, for an uncharged and linear dielectric fluid at rest and in local equilibrium in an electrostatic or magnetostatic field, the definition of stress tensor employed in continuum mechanics is inconsistent with the assumption that the stress tensor depends only on the local values of mass density, temperature, electric- or magnetic-field components and the derivatives of these quantities with respect to space and time.     

On the plastic equation of state with one structure variable

Summary The general expression for a plastic equation of state with one structure variable and with a scaling relationship is presented. It is demonstrated that this equation can be written, in general, in terms of stress, plastic strain rate and a function of plastic strain. Finally, the results are compared with previous formulations of the problem presented in the literature to show that they are particular cases of the general formalism presented. The authors of this paper have agreed to not receive the proofs for correction.     

Magnetostatic stresses on a superconductor in a dielectric fluid

Summary The stresses which act on the surface of a superconductor surrounded by an isotropic dielectric fluid at rest are evaluated. Moreover, it is proved that there exists an infinite set of second-order tensors which yield these stresses. The magnetic Helmoltz stress tensor belongs to this set.     

Total Current Operator and its Classical Correspondence for Particles Bounded in Central Force Fields

When a particle is bounded in a central force field, the only nonvanishing component of the mean value for current density is along the azimuthal direction; and the total current can therefore be defined. It is found that the total current is in fact a mean value of a newly defined total current operator in the quantum mechanical state. Not only the total current operator itself but also the mean total current has exact classical correspondence.     

Thermodynamic equilibrium in dielectric fluids

Summary A rigorous deduction of the thermodynamic-equilibrium condition is provided for a homogeneous, uncharged and linear dielectric fluid contained in an electrostatic field. Contrary to the previous ones, this deduction does not postulate the existence of a mechanical stress tensor and of a body force density in the polarized fluid. Then, the equilibrium condition is employed to obtain the mass density distribution of the fluid and to present a correct proof of the well-known formula for the attractive force between the plates of a plane-parallel capacitor immersed in the fluid.