高斯束谐振系统对引力波频率和方向的选择效应

高斯束谐振系统为早期宇宙遗留的随机高频引力波的探测开启了一个非常重要的窗口.计算结果表明，当入射引力波频率和高斯束不同时，高斯束谐振系统产生的一阶扰动光子流没有观测效应；当入射引力波的传播方向与高斯束对称轴的正方向不同时，高斯束谐振系统产生的一阶扰动光子流将降低几个数量级，即高斯束谐振系统只对沿某一特定方向传播的高频遗迹引力波产生有效的响应.因此，高斯束谐振系统对高频遗迹引力波的频率和传播方向具有良好的选择效应. 关键词： 高斯束谐振系统 高频遗迹引力波 一阶扰动光子流 频率选择效应 方向选择效应     

束-离子通道电磁模式的边界效应分析

考虑束-离子通道边界上等离子体电子可能发生的扰动，导出了TM模本征方程的理论式.通过对理论结果的数值模拟计算，在阶跃边界情况下将束-离子通道与一般介质波导的电磁关系进行了比较，发现束-离子通道可以通过改变等离子体频率来控制其工作模式.分析对照扰动电荷边界与阶跃边界对束-离子通道电磁模式的影响，观察到在扰动电荷边界情况下，束-离子通道在低频区域(ω＜ω_p,ω_p为等离子体频率)内截止频率显著提高，并在高频区域(ω>ω_p)内出现了新的电磁模式.研究结果对离子通道激光(ICL)和离子通道电子回旋脉塞(ICECM)的设计提供重要的理论依据. 关键词： 束-离子通道 阶跃边界 扰动电荷边界 电磁模式     

二维相对论运动等离子体的介电率张量

定义了相对论性运动等离子体的物理模型.利用荷流体的微扰理论，研究了该系统二维扰动现象及背景离子下的束-波互作用问题，导出了该系统的介电率张量.研究表明，相对论运动等离子体系统属复杂的色散荷流体介质并呈复杂的空间电磁不均匀性.数值模拟计算给出了相对论运动等离子体系统的介电率对波频率、电子能量以及空间坐标的响应. 关键词： 等离子体 荷流体 介质 电磁理论     

轴对称非均匀弹性介质中引力波对声子的作用效应

采用Ｓｅｒｅｂｒｙａｎｙ的复空间中的复坐标法，讨论了轴对称非均匀弹性介质中引力波对声子的作用效应，并给出了由引力波产生的激发力的表达式和相应的声子解。解的形式表明，平行于对称轴方向传播的引力波只对声子场的径向分量、切向分量产生扰动，垂直于对称轴方向传播的引力波则对声子场的径向分量、切向分量和轴向分量均产生扰动，扰动强度取决于切变模量径向分布函数的具体形式和引力波的振幅。此外，本文还将所得结果与含有螺旋位错的拓扑声子空间中引力波的扰动效应作了比较。 关键词：     

基于零折射磁性特异电磁介质的波前调控

本文基于二维磁性柱周期阵列设计了具有等效零折射率的磁性特异电磁介质. 通过多重散射理论计算体系的光子能带和等效介质理论提取体系的等效电磁参量可以确定该磁性特异电磁介质可以实现等效介电常数和等效磁导率同时为零. 利用该双零磁性特异电磁介质可以实现电磁波在无相位延迟下的传输, 从而可以调控电磁波的空间相位变化. 进而, 通过设计具有不同电磁波输出界面的构型实现了高斯光束的波前由平面转变成柱面, 还可以实现高斯光束的聚焦和高斯光束的分束. 也可以根据需要设计具有更为一般的输出界面, 实现更为多样的电磁波波前的调控. 而且, 磁性材料的电磁特性可以通过温度和外加磁场进行调制, 因此该双零磁性特异电磁介质的工作频率可以灵活控制, 这更便于电磁波器件的设计和应用.     

X射线透明

通常气体原子吸收一定频率的光，这种频率对应于气体原子中两个量子能级之间的能量差。但是如果存在第三个能级，则可能产生所谓电磁诱发透明的量子现象。为产生这种现象，用一束激光作为抽运束，造成第二个与第三个能级的相干叠加，成为所谓的“缀饰态”。如果调谐得适当，由第一态到两个缀饰态的跃迁发生相消干涉。     

非均匀强激光在等离子体中的细丝不稳定性

本文研究了包含着高斯形初始扰动的非均匀强电磁辐射在等离子体中的细丝不稳定性.计算并讨论了细丝不稳定性与初始扰动的强度、横向尺寸和初始等离子体电子密度的关系.结果表明,叠加在线偏振平面电磁波上的高斯型大扰动,在等离子体中传播不远就将崩裂.     

光的压缩态

光学这门古老的学科在本世纪六十年代得到了革命性的发展．随着量子理论深入其中，又一次开创了光学的新纪元，预言并且产生了新的辐射场，诸如反聚束态、亚泊松统计光场、压缩态等．其中以压缩态最为引人注意，在先通讯和引力波检测中具有可能的应用前景，因此在近几年得到了很大的发展．本文从原理上对光的压缩态进行描述，同时也介绍压缩态研究的最新结果．     

扩散过程中弱相干光场的退相干

研究了扩散过程中弱相干光场量子特性的演化.利用正规乘积、反正规乘积和Weyl编序算符内的积分技术,采用热纠缠态表象求解密度矩阵主方程,利用Kraus算符给出扩散过程中密度算符解的表达式,导出初态为弱相干态的量子态密度算符演化规律.讨论了扩散对光场压缩效应和反聚束效应的影响.结果表明:随着扩散过程的进行,弱相干场压缩深度和压缩范围均在减小;扩散初期光场呈反聚束效应,扩散时间大于一定值后反聚束效应消失.     

狭窄波束型高频引力辐射与电磁场的作用效应

从弱引力场的Einstein-Maxwell方程出发,讨论了晶体空间阵列的狭窄波束型高频引力辐射与电磁场的作用效应,并给出了扰动解。计算表明,在TT(Transvese Traceless)坐标系中,最优辐射方向的引力波束是纯十型极化的,并可使同频的电磁波产生倍频的扰动效应,使静态电磁场产生与时间成线性关系的累积扰动效应。对于任意方向上的引力辐射波束,在垂直于引力波矢的平面内仍然是纯十型极化的。在高频辐射和实验室典型尺度条件下,TT坐标系与Fermi坐标系的差异是可以忽略的。 关键词：     

Pauli equation for a particle in metric and electromagnetic fields

A Pauli theory (Pauli equation and definition of probability current and density) for a particle in weak metric and arbitrary electromagnetic fields is treated. To formulate non-relativistic quantum mechanical problems in arbitrary electromagnetic fields and weak metrics (non-inertial systems, gravitational fields which are distant fields of arbitrary distribution of masses, gravitational waves) it is not necessary to make use of the general-relativistic Dirac equation. Close analogies to the known Pauli theory with electromagnetic fields exist. For different metric fields the corresponding Hamiltonians are given. For quantum systems (H-atoms) which are disturbed by a homogeneous gravitational field and a gravitational wave the resulting shift of energy levels and the transition probability is calculated.     

Interaction between gravity and moving superconductors

We propose a unified phenomenological theory to investigate the interaction between arbitrarily moving superconductors and gravitational fields including the Newtonian gravity, gravitational waves, vector transverse gravitoelectric fields, and vector gravitomagnetic fields. In the limit of weak field and low velocity, the expressions for the induced electromagnetic and gravitational fields in the interior of a moving superconductor are obtained. The Meissner effect, London moment, DeWitt effect, effects of gravitational wave on a superconductor, and induced electric fields in the interior of a freely vibrating superconductor are recovered from these two expressions. We demonstrate that the weak equivalence principle is valid in superconductivity, that Newtonian gravity and gravitational waves will penetrate either a moving superconductor or a superconductor at rest, and that a superconductor at rest cannot shield either vector gravitomagnetic fields or vector transverse gravitoelectric fields.     

高频引力波对环形波导中电磁波的调制作用

讨论了垂直入射的、频率为ω_g的平面高频引力波对环形波导管中频率为ω_e的电磁波的调制作用．一般情况下，在波导管中与引力波传播方向垂直的对称平面附近，电磁波的能流密度会出现三种新的频率成分（2ω_e±ω_g）和ω_g．在ω_g》ω_e时，能流密度振幅的相对调制量与引力波的无量纲振幅h₀数量级相同．特别是当ω_g，ω_e和电磁波绕波导传播的绕行频率ω₀满足关系ω_g＝2ω_e》ω₀时，由于类似于共振的机制，能流密度会出现比h₀大几个数量级的振幅相对调制量．这个结果不会由于参数的微小改变而消失，这对于探测极微弱的引力辐射信号将是十分重要的 关键词：     

Test of a model coupling of electromagnetic and gravitational fields by using high-frequency gravitational waves

Models of the coupling of electromagnetic and gravitational fields have been studied extensively for many years. In this paper,we consider the coupling between the Maxwell field and the Weyl tensor of the gravitational field to study how the wavevector of the electromagnetic wave is affected by a plane gravitational wave. We find that the wavevector depends upon the frequency and direction of polarization of the electromagnetic waves, the parameter that couples the Maxwell field and the Weyl tensor, and the angle between the direction of propagation of the electromagnetic wave and the coordinate axis. The results show that this coupling model can be tested by the detection of high-frequency gravitational waves.     

Nonlinear Evolution of a Gaussian Wave Perturbation in the Presence of a High Power Electromagnetic Plane Wave in the F Region Ionosphere

The interaction of a high power electromagnetic plane wave of uniform intensity with a weak electromagnetic Gaussian wave has been studies analytically. The two waves propagate vertically with almost the same frequency in the F region ionosphre. It is seen that the Gaussian wave acquires an oscillatory structure due to the nonlinear coupling of the strong plane wave and the weak Gaussian wave and the amplitude of these fluctuations grows with height. The growth, however, occurs only above a certain altitude z₀, which is determined by the plasma and wave parameters.     

Application of types-N and -O spaces to examples of exact solutions of the gravitational equations

Analysis of the exact solutions of the gravitational equations corresponding to the collision of two gravitational plane waves (typeN) and light-like beams (typeO) and also a Kerr-Schild wave metric with conformally flat background is used to formulate theorems that indicate the resulting type of spacetime if the initial gravitational fields belong to typesN andO. A type-D Weyl matrix always appears, which is due to the nonlinear super-position of gravitational fields, in contrast to the superposition of weak gravitational fields, when the sum of the Weyl matrices for the initial fields corresponds to dropping nonlinear terms in both the curvature tensor and the field equations.Work performed under the auspices of the Russian State Scientific-Technical Program Astronomiya.Krasnoyarsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 77–82, May, 1995.     

A minimal relativistic model of gravitation within standard restrictions of the Classical Theory of Fields

The minimal relativistic model of gravitation on the basis of the gauge-invariant theory of the linear scalar massless field is suggested. The principle of the multiplicative inclusion of gravitational interaction, the requirements being that the simplicity and invariance of the theory under the allowed (gauge) transformation of potential Ф → Ф′ = Ф + const as the basis of the approach, is used. A system of gauge-invariant gravitational field and matter equations is obtained and an energy-momentum tensor with a positively defined density of the field energy is constructed. The exact solutions to equations for the central static field and for fields of spherically symmetric and plane gravitational waves in the free space and in the material media are obtained.     

Some exact solutions of the Plebański and Pellegrini tetrade gravitational equations

Tetrades are found which satisfy the gravitational equations found recently by Plebaski and Pellegrini in the case of Peres and Bondi plane gravitational waves and the energy density and energy-current density in these waves are determined.