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：     

S-dual模型产生的原初黑洞和次级引力波

在S-dual暴涨模型中通过在非正则动能项中引入峰值函数,可产生丰度可观的原初黑洞和次级引力波.该模型分别在10¹²,10⁸和10⁵ Mpc^-1对原初密度扰动的功率谱进行放大,产生了质量量级分别为10^-13太阳质量、地球质量、行星质量的原初黑洞,以及峰值频率分别为毫赫兹、微赫兹、纳赫兹的次级引力波.其中在10^-13太阳质量附近的原初黑洞可以解释全部的暗物质,产生的次级引力波能被未来的空间引力波探测器探测到.     

普朗克卫星:揭开宇宙深层次的秘密

文章对宇宙微波背景辐射这一学科做了简单的介绍,并根据普朗克卫星2015年的主要宇宙学结果,重点阐述了测定宇宙学参数、测量引力透镜、测量B-模式极化及其与南极BICEP实验的关系、检验宇宙暴胀模型、检测暗能量模型,以及寻找"丢失的重子物质"等问题,并对观测宇宙学未来的发展进行了展望。     

静电除尘用大功率高频高压电源预测控制研究

静电除尘用大功率高频高压电源系统具有非线性、时变性、迟滞性等特点,需要一类数学模型要求低、自适应能力强的非线性控制方法。以自主研发的静电除尘用大功率高频高压电源为研究对象,基于现场实际电源系统试验结果,采用最小二乘法辨识系统的近似传递函数模型,最后设计了一种新颖的基于动态矩阵算法(DMC)的模型预测控制器,实现针对电源输出电压的控制。仿真结果表明,该算法具有稳定性好、自适应强等优点,并具有良好的控制效果。     

High-frequency gravitational waves having large spectral densities and their electromagnetic response

Various cosmology models, brane oscillation scenarios, interaction of interstellar plasma with intense electromagnetic radiation, and even high-energy physics experiments （e.g., Large Hadron Collider （LHC）） all predict high frequency gravitational waves （HFGWs, i.e., high-energy gravitons） in the microwave band and higher frequency region, and some of them have large energy densities. Electromagnetic （EM） detection to such HFGWs would be suitable due to very high frequencies and large energy densities of the HFGWs. We review several typical EM detection schemes, i.e., inverse Gertsenshtein effect （G-effect）, coupling of the inverse G effect with a coherent EM wave, coupling of planar superconducting open cavity with a static magnetic field, cylindrical superconducting closed cavity, and the EM sychro-resonance system, and discuss related minimal detectable amplitudes and sensitivities. Furthermore, we give some new ideas and improvement ways enhancing the possibility of measuring the HFGWs. It is shown that there is still a large room for improvement for those schemes to approach and even reach up the requirement of detection of HFGWs expected by the cosmological models and high-energy astrophysical process.     

基于面元散射体集合模型的水下复杂物体高频回波特性研究

复杂物体的高频回波特性研究对水下三维成像具有重要意义。本文针对SYSNOISE软件计算内存不足的问题,提出了面元散射体集合模型,有效减小了网格划分产生的节点数量。通过对刚性曲面回波信号的模拟,表明仿真信号可以用来准确成像,初步论证了面元散射体集合模型的正确。波束形成成像结果表明,本文方法可在成像结果中较好地显示刚性曲面的三维形状,对于水下目标的识别有着重要的意义。     

引力、引力波和引力波的探测

简要地回顾了引力和引力波概念的由来,以及人们为探测引力波所作的各种努力．     

电子储存环中离子俘获不稳定性和高频清洗的模拟

介绍了用强–弱模型对电子储存环中离子俘获不稳定性和高频清洗机制进行模拟研究的结果.模拟结果可合理地解释在合肥光源(HLS)储存环上观察到的现象.     

用零输出的设备探测引力波

理论估计传到地球上的引力波非常弱,激光干涉引力波探测器被设计用来探测引力波,在没有引力波传来时,激光干涉引力波探测器应该是零输出。为达到这样的目的,必须和众多的噪声作斗争。     

地下引力波探测器

日本物理学家建成了世界上第一个地下引力波探测器.初步检验表明,由于地下的环境噪声减低使得在矿井中的激光干涉仪引力波小型观测站(LISM )能够稳定地工作.探测器安置在超神冈中微子探测器附近地下1km深处.引力波是时空结构中的波动,可由空间中大块物质加速而产生.然而,即使像     

Some High-Frequency Gravitational Waves Related to Exact Radiative Spacetimes

A formalism is introduced which may describe both standard linearized waves and gravitational waves in Isaacson's high-frequency limit. After emphasizing main differences between the two approximation techniques we generalize the Isaacson method to non-vacuum spacetimes. Then we present three large explicit classes of solutions for high-frequency gravitational waves in particular backgrounds. These involve non-expanding (plane, spherical or hyperbolical), cylindrical, and expanding (spherical) waves propagating in various universes which may contain a cosmological constant and electromagnetic field. Relations of high-frequency gravitational perturbations of these types to corresponding exact radiative spacetimes are described.     

Do gravitational waves carry energy‐momentum and angular momentum?

We show that gravitational waves which possess a non‐vanishing Riemann tensor R_iklm ≠ 0 always carry energy‐momentum and angular momentum. Our proof uses canonical superenergy and supermomentum tensors for the gravitational field.     

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     

Characteristic Features of Gravitational Wave Lensing as Probe of Lens Mass Model

To recognize gravitational wave lensing events and being able to differentiate between similar lens models will be of crucial importance once one will be observing several lensing events of gravitational waves per year. In this work, the lensing of gravitational waves is studied in the context of LISA sources and wave-optics regime. While different papers before the studied microlensing effects enhanced by simultaneous strong lensing, the focus is on frequency (time) dependent phase effects produced by one lens that will be visible with only one lensed signal. It is shows how, in the interference regime (i.e., when interference patterns are present in the lensed image), one is able to i) distinguish a lensed waveform from an unlensed one, and ii) differentiate between different lens models. In pure wave-optics, on the other hand, the feasibility of the study depends on the signal-to-noise ratio of the signal and/or the amplitude of the lensing effect. To achieve these goals, the phase of the amplification factor of the different lens models and its effect on the unlensed waveform is studied, and the signal-to-noise calculation to provide some quantitative examples is exploited.     

物质纯重力场部分的能量-动量张量研究

认为物质的质量(能量)存在形式可分为两部分，一部分是以纯物质形式存在的，另一部分是以纯重力场形式存在的.物质质量(能量)这两种形式各自对应着相应的能量 动量张量，物质总的能量-动量张量可表示为Tμν=T(Ⅰ)μν+T(Ⅱ)μν,这里，T(Ⅰ)μν，T（Ⅱ）μν分别代表物质纯物质部分和纯重力场部分的能量-动量张量.通过类比电磁理论，定义：ωμ≡-c2gμ0/g00,并引入一个反对称张量Dμν=ωμ/xν-ων/xμ，则物质纯重力场部分的能量-动量张量为T(Ⅱ)μν=(DμρDρν-gμνDαβDαβ/4 关键词： 能量-动量张量 纯重力场 重力场方程 标量重力势 矢量重力势     

A new method to test the cosmic distance duality relation using the strongly lensed gravitational waves

We propose a new method to test the cosmic distance duality relation using the strongly lensed gravitational waves. The simultaneous observation of the image positions, relative time delay between different images, redshift measurements of the lens and the source, together with the mass modelling of the lens galaxy, provide the angular diameter distance to the gravitational wave source. On the other hand, the luminosity distance to the source can be obtained from the observation of the gravitational wave signals. To our knowledge this is the first time a method is proposed to simultaneously measure the angular diameter distance and the luminosity distance from the same source. Hence, the strongly lensed gravitational waves provide a unique method to test the cosmic distance duality relation. With the construction of the third generation gravitational detectors such as the Einstein Telescope, it will be possible to test the cosmic distance duality relation with an accuracy of a few percent.     

含物质纯重力场部分贡献的静态和稳态重力场研究

给出了包含重力场贡献在内具有宇宙因子项最普遍形式的重力场方程为Rμν-gμνR/2+λgμν=8πG(T(Ⅰ)μν+T(Ⅱ)μν)/c4，这里λ为Einstein宇宙常数，Ｔ（Ⅰ）μν，Ｔ（Ⅱ）μν分别代表物质纯物质部分和纯重力场部分的能量-动量张量.物质纯重力场部分的能量-动量张量表述为T(Ⅱ)μν=(DμρＤρν-gμνＤαβＤαβ/4)/4πG，式中Dμν的定义为Ｄμν＝ωμ／xν-ων／xμ，ωμ≡-c2gμ0/g00.并用重力场贡献在内最普遍形式的重力场方程分别研究了几个大家所熟悉的静态和稳态重力场，像带有Einstein宇宙因子λ项球对称纯物质球外部静态度规、静态荷电球外部度规、匀速转动星体外部度规及理想纯物质星体内部静态平衡等,并进行了讨论. 关键词： 能量动量张量 重力场方程 静态重力场 稳态重力场     

The prospects of using gravitational waves for constraining the anisotropy of the Universe

The observation of GW150914 gave a new independent measurement of the luminosity distance of a gravitational wave event. In this paper, we constrain the anisotropy of the Universe by using gravitational wave events.We simulate hundreds of events of binary neutron star merger that may be observed by the Einstein Telescope. Full simulation of the production process of gravitational wave data is employed. We find that 200 binary neutron star merging events with the redshift in (0,1) observed by the Einstein Telescope may constrain the anisotropy with an accuracy comparable to that from the Union2.1 supernovae. This result shows that gravitational waves can be a powerful tool for investigating cosmological anisotropy.