On the phenomenological theory of the linear electrooptical effect in uniaxial crystals

The linear electrooptical effect in uniaxial crystals is considered with the aid of direct tensor methods. Covariant expressions for finding biradials and ray refractive indices are developed. A general expression is derived relating the nonlinear optical polarizability parameters and the electrooptical properties of a crystal. The results are applied to cuts of uniaxial ammonium dihydrogen phosphate (ADP), potassium dihydrogen phosphate (PDP), and quartz crystals often used for light modulation. The induced phase differences between the light waves propagating in such crystals are found for the field orientations considered.     

Kinematic and electrooptical anharmonicity in the semiempirical intensity theory of IR and raman spectra of polyatomic molecules

Saratov State University, 83 Astrakhanskaya Str., Saratov, 410601, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 6, pp. 49–57, November–December, 1995.     

Scattering theory of the linear Boltzmann operator

In time dependent scattering theory we know three important examples: the wave equation around an obstacle, the Schrödinger and the Dirac equation with a scattering potential. In this paper another example from time dependent linear transport theory is added and considered in full detail. First the linear Boltzmann operator in certain Banach spaces is rigorously defined, and then the existence of the Møller operators is proved by use of the theorem of Cook-Jauch-Kuroda, that is generalized to the case of a Banach space.     

衍射现象对高精度偏转器设计的影响

基于波动光学理论,计算了由衍射、球差和色差三者共同作用的电子束斑电流分布,得到了电子束斑的精确信息和电子束曝光机的轴上分辨率。针对某一个具体系统的不同电子束孔径角,以偏转器的位置和相互转角为变量进行了偏转系统的优化设计;综合考虑了电子光学系统的衍射、轴上像差和偏转像差三者与光阑孔径角的不同关系。得到了光柱体的最佳总体性能,保证了电子束曝光机的高分辨率和均匀性。     

About the exactness of the linear response theory

For quantum lattice systems with finite range potentials and integrable space clustering, we prove the linearity of the response theory when dealing with fluctuation observables.     

Comments on the linear theory of the gyrotron

The authors present alternative methods for the calculation of the starting current in a gyrotron, and an analysis of the excitation of parasitic modes in gyrotrons operating in a given mode. Numerical examples are presented which check the validity of some of the assumptions made, and the extension of the formalism to the investigation of the stability of an operating mode when parasitic modes can be excited (mode competition) is also discussed. Results from the problem formulation, which is based on the cold-cathode model of Borie and Jodicke (1987), are compared with both linear and fully nonlinear models. These results illustrate the importance of using a correct model for the field profile and the influence of numerical uncertainties on the results obtained using a linear theory for mode competition. It is noted that the results obtained using the nonlinear theory of mode competition are usually numerically more stable and easier to interpret     

Some applications of the theory of linear absorption

Linear absorption has been used to measure the optical density for the hyperfine structure (hfs) of the 4046. 56 and 4358. 35 A lines of mercury.We are indebted to Professor N. A. Prilezhaeva and to N. G. Preobrazhenskii for discussions and advice.     

Semiclassical results in the linear response theory

We consider a quantum system of non-interacting fermions at temperature T, in the framework of linear response theory. We show that semiclassical theory is an appropriate framework to describe some of their thermodynamic properties, in particular through asymptotic expansions in ? (Planck constant) of the dynamical susceptibilities. We show how the closed orbits of the classical motion in phase space manifest themselves in these expansions, in the regime where T is of the order of ?.     

On the most general linear theory of gravitation

The most general field theory of gravitation is analyzed both group theoretically as well as physically. The field equations are solved by means of an algebraic method and it is found that any field theory of gravitation contains only one essential parameter which is correlated to the spin 0 content of the field. Further it turns out that any theory of gravitation must contain a nonvanishing spin 0 part, but general relativity is distinguished by the fact that its spin 0 component cannot be radiated.     

Analysis and optimization of blocks in high-frequency sections of linear accelerators and deflectors of charged particles using an equivalent circuit

Analysis and optimization of blocks in high-frequency sections of linear accelerators and defectors of accelerated particles is performed using an equivalent circuit. This circuit correctly simulates the lowest accelerating mode as well as the first dipole mode of the E-type for various structures consisting of coupled cells. Analytic expressions are derived for parameters of individual cells of sections for which traveling waves with a preset form of oscillations propagate at a given frequency; optimization of the parameters of the input and output wave-type transformers is carried out. Simple analytic expressions are considered for calculating the complex reflection coefficient of a section in a certain cross section of the lead-in waveguide. The sections may contain identical cells as well as different cells.     

The linear theory of gravitation in the radiation gauge

A global gauge for the linear theory of gravity is given which avoids the (In(R))/R problem of harmonic coordinates. Consequently it is possible to do 1/R expansions for precisely those null sources which lead to difficulties in the harmonic gauge. This is important, for example, in second order calculations where the first order field is a gravitational wave. This gauge makes manifest the two degrees of freedom for the dynamic fields. In it the second time derivative of the metric itself has physical significance since R _oioj=–1/2h_ij.Work supported in part by NSF Grant No. GP-13959.     

On the linear response theory of infinite quantum systems

The perturbation of a C¹-dynamics α by a time-dependent unbounded 1-derivation of the form μ?(t)δ′ is considered. The existence of the perturbed dynamics and that of the linear responce oftthe C¹-dynamical system ($\text{A}$, $\text{R}$, α) is shown. The existence of the corresponding generalized susceptibility and some convergence problems are discussed.