Some problems of classical electrodynamics

In this lecture, I discuss issues that usually escape attention of students in electrodynamics. These are the questions of (1) what the photon observed in nature “looks like,” (2) how an interference pattern arises from a source containing a lot of incoherently emitting atoms, and (3) how light “slows down” in a medium. Answers to these questions, if discussed at all, are scattered over various textbooks. Here, I follow our textbook [1].     

Current electric quadrupole moments of atoms and nuclei

It is shown that current electric multipoles exist. Their field is electrostatic and it is unrelated to the existence of a net electric charge. At long range, it is the same as the field of the corresponding charge electric multipoles. Current electric multipoles arise during the motion of magnetic multipoles. An orbital motion of magnetic dipoles, a precession of a current-carrying loop, and the motion of magnetic quadrupoles all lead to current electric quadrupole moments. Expressions for the current electric quadrupole moments of atoms and nuclei are derived.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 53–58, July, 1991.The author wishes to thank S. A. Kuten' and V. I. Rapoport for useful comments offered during the writing of this paper and for a discussion of the results.     

Comments on “determinism,realism, and Stapp's 1985 proof of nonlocality”

An earlier argument by the author, that Stapp's 1985 proof of quantum locality contains an implicit element of realism, is elaborated. Refuted thereby is Clifton's criticism that the author's argument was based on a misinterpretation of counterfactual analysis.     

The exact equation of motion for a two level system. Zubarev like approach

A simple model, one spinS=1/2 interacting with an alternating transverse field and with a single mode of a boson field, treated as an open system, is rigorously investigated. An approach based on the Zubarev method is applied. An integro-differential equation for a mean value of the Zeeman operator is derived. Kernels of this equation are defined as solutions of some functional (integral) equations. A particular case, known as the Jaynes-Cummings model in quantum optics, is considered. The Markovian limit of the integro-differential equation for the Jaynes-Cummings model leads to a simple relaxation equation.Supported in part by the Polish Academy of Sciences.The author would like to thank Prof. A. Pawlikowski for his continual interest in the present work and useful comments and discussions. The author is also indebted to Dr. E. Malec and Dr. J. Aksamit for their help during the preparation of this paper.     

谈地方高校基础物理实验室的规范化管理

本结合工作实践、调查和研究,分析了高校基础实验室进行科学、规范化管理的必要性,论述了规范管理基础实验室体系的具体内容。     

On lower hybrid wave scattering by plasma density fluctuations

The author thanks R. Klíma for bringing the problem of wave scattering to the author's attention. Further, the author is obliged to J. Preinhaelter for his kind permission to use the computed spectra /3/ (full curves, figs. 1, 2) prior to publication.     

Cryptanalysis of a chaos-based cryptosystem with an embedded adaptive arithmetic coder

In this paper,we analyse a new chaos-based cryptosystem with an embedded adaptive arithmetic coder,which was proposed by Li Heng-Jian and Zhang J S (Li H J and Zhang J S 2010 Chin.Phys.B 19 050508).Although this new method has a better compression performance than its original version,it is found that there are some problems with its security and decryption processes.In this paper,it is shown how to obtain a great deal of plain text from the cipher text without prior knowledge of the secret key.After discussing the security and decryption problems of the Li Heng-Jian et al.algorithm,we propose an improved chaos-based cryptosystem with an embedded adaptive arithmetic coder that is more secure.     

Three-dimensional mid-infrared photonic circuits in chalcogenide glass

We report the fabrication of single-mode buried channel waveguides for the whole mid-IR transparency range of chalcogenide sulphide glasses (λ ≤ 11 μm), by means of direct laser writing. We have explored the potential of this technology by fabricating a prototype three-dimensional three-beam combiner for future application in stellar interferometry that delivers a monochromatic interference visibility of 99.89% at 10.6 μm and an ultrahigh bandwidth (3-11 μm) interference visibility of 21.3%. These results demonstrate that it is possible to harness the whole transparency range offered by chalcogenide glasses on a single on-chip instrument by means of direct laser writing, a finding that may be of key significance in future technologies such as astrophotonics and biochemical sensing.     

Energy analysis of a toroidal magnetohydrodynamic plasma with fluid motion

Summary The relaxation process in an ideal magnetohydrodynamic (MHD) plasma with fluid velocity and enclosed in a toroidal vessel has been discussed. The expressions for the field parameters and the energy state of the system have been derived. The expression for the minimum energy state of the system has been deduced. An analysis of the conservation of energy of the system in the presence of weak and strong magnetic fields has also been presented. The author of this paper has agreed to not receive the proofs for correction. This work was commenced and partly completed during author's short stay at I.C.T.P.-Trieste, Italy, in 1988.     

光学教学中的偏振度定义

分析了当前国内部分光学教材中对偏振度定义的歧义,指出依照电矢量在不同方向上的强度来定义偏振度的不完整性,并由此提出教学中的注意点．     

A generalization of variable phase equation

This paper describes a new formulation of phase equation based on a decomposition of wave function into two parts. An equation closely related to the WKB approximation is derived and solved numerically with exponential and Wood-Saxons potential.The author is indebted very much to Doc. J.Kvasnica CSc for the valuable discussions and interest in this work.     

Dye-doped liquid crystals as high-resolution recording media

Light-induced anchoring of the molecular director is reported to be an efficient method for writing permanent holographic gratings in dye-doped liquid crystals. We have achieved higher sensitivity and spatial resolution in these materials with other methods. An energy density as low as 10(-1) J/cm(2) was sufficient to write gratings with a resolution higher than 100 lines/mm.     

Implementation of a constrained Ritz series modeling technique for acoustic cavity-structural systems

A prior study [Ginsberg, J. H. (2010b). J. Acoust. Soc. Am. 127, 2749-2758] used Ritz series in conjunction with Hamilton's principle to derive general equations describing the time domain response of an acoustic cavity bounded by an elastic structure. The equations of motion are supplemented by constraint equations that explicitly enforce velocity continuity at the cavity's surface. These constraints are imposed by the surface traction, which is represented by unknown coefficients of Ritz-type series. The resulting set of equations are differential-algebraic type. Three methods are presented to convert the governing equations to forms that are familiar to structural acoustics, including one that transforms them from differential-algebraic type to the standard ordinary differential equations associated with linear multi-degree-of-freedom vibratory systems. In cases where only the structure is excited, the formulation offers options as to how displacement/velocity boundary conditions on the nonstructural boundary are enforced, as well as whether zero pressure boundary conditions are enforced at all. An example of a one-dimensional waveguide that is closed at one end by an oscillator is used to explore the quality of solutions obtained from each of these options. Results for natural frequencies and mode functions are examined for accuracy and convergence.     

UV filaments and their application for laser-induced lightning and high-aspect-ratio hole drilling

Experimental results pertaining to 1 ps pulse-width filaments at 248 nm are reviewed. The theoretical studies presented in this paper show that scaling those filaments to ns pulse-widths should enable us to trap up to 1 J in a single channel. We will show how the use of an aerodynamic window can lead to applications such as laser-induced lightning and high-aspect-ratio hole drilling. Received: 23 January 2003 / Accepted: 8 February 2003 / Published online: 28 May 2003 RID="*" ID="*"Corresponding author. Fax: +1-505/277-4026, E-mail: jcdiels@unm.edu     

The non-linear theory of instability of non-potential plasma waves in an oscillating discharge

The paper presents an analysis of the non-linear effects produced by the instability of non-potential plasma waves in an oscillating discharge [J. Václavík: Czech. J. Phys.B 15 (1965), 11]. An equation is derived describing a stationary weakly-turbulent state of the plasma, with the aid of which an estimate is made of the spectrum function of the electric field of the waves, and of the coefficient of turbulent diffusion of the plasma.In conclusion the author wishes to express his thanks to the members of the High Temperature Plasma-2 Department for their valuable discussions.     

Plastic deformation of the precipitation hardened Cu-0·7 at.% Ti single crystals

Single crystals Cu-0·7 at.% Ti were deformed at room temperature in tension. The effect of the annealing time on the shape of the stress-strain curves has been investigated. The change of the stress-strain curve consisting of three regions to that one with one region only is observed if the annealing time is increased. There is a maximum in the dependence of CRSS on the annealing time fort=140 hours.The author wishes to thank to Dr. P.Kratochvil who stimulated this research and helped him. It is also the author's pleasure to thank to Ing. J.Bican of the Research Institute of Metals, who kindly prepared of Cu-Ti alloys. Also the determination of Ti content in all samples by Dr. J.Vrbský and Dr. Z.Ksandr of the Chemical College is acknowledged.     

Irreversibility in quantum scattering

The stationary quantum scattering is analyzed with the result that states which are not described by a complete set of observables are irreversible. The origin of irreversibility is shown to consist in impossibility to correlate phases of partial waves making up time reversed states. The same mechanism is responsible for irreversibility of any time-dependent scattering. Evidence is however given that the classical limit of irreversible scattering is reversible.Dedicated to Professor J. Kvasnica on the occasion of his sixtieth birthday.The author wishes to thank Doc. Erkki Brändas (Department of Quantum Chemistry, Uppsala University, Uppsala, Sweden) for calling author's attention to scattering theory as a possible source of information concerning irreversibility, Prof. Jozef Kvasnica (Department of Mathematical Physics, Charles University, Prague) for critical comments making the paper more self-consistent and Dr. Samuel Mockoviak (Department of Theoretical Physics, P. J. afárik University, Koice) for helpful discussions.     

The Schrödinger equation in quantum field theory

Some aspects of the Schrödinger equation in quantum field theory are considered in this article. The emphasis is on the Schrödinger functional equation for Yang-Mills theory, arising mainly out of Feynman's work on (2+1)-dimensional Yang-Mills theory, which he studied with a view to explaining the confinement of gluons. The author extended Feynman's work in two earlier papers, and the present article is partly a review of Feynman's and the author's work and some further extension of the latter. The primary motivation of this article is to suggest that considering the Schrödinger functional equation in the context of Yang-Mills theory may contribute significantly to the solution of the confinement and related problems, an aspect which, in the author's opinion, has not received the attention it deserves. The relation of this problem with certain others such as those of quarks, superconductivity, and quantum gravity is considered briefly, together with certain basic aspects of the formalism that may be of interest in their own right, especially for the beginner.Dedicated to Professor Fritz Rohrlich on the occasion of his seventieth birthday, May 12, 1991.