共查询到19条相似文献,搜索用时 78 毫秒
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讨论了垂直入射的、频率为ωg的平面高频引力波对环形波导管中频率为ωe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(2ωe±ωg)和ωg.在ωg》ωe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ωg,ωe和电磁波绕波导传播的绕行频率ω0满足关系ωg=2ωe》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: 相似文献
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GW170817实现了基于“标准汽笛”的首次哈勃常数&;amp;lt;em&;amp;lt;H&;amp;lt;/em&;amp;lt;&;amp;lt;sub&;amp;lt;0&;amp;lt;/sub&;amp;lt;测量,开启了标准汽笛宇宙学的序幕。正在进行的双中子星并合引力波观测,有望在5年内测量&;amp;lt;em&;amp;lt;H&;amp;lt;/em&;amp;lt;&;amp;lt;sub&;amp;lt;0&;amp;lt;/sub&;amp;lt;到约2%精度,提供解决&;amp;lt;em&;amp;lt;H&;amp;lt;/em&;amp;lt;&;amp;lt;sub&;amp;lt;0&;amp;lt;/sub&;amp;lt;危机的独立而珍贵的数据。下一代的引力波实验,则将通过标准汽笛方法,精确测量宇宙膨胀速度和宇宙大尺度结构,限制暗能量状态方程,在宇宙学尺度上检验广义相对论。 相似文献
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1925年英年早逝的弗里德曼堪称大爆炸宇宙学之父.然而,他杰出的贡献常常被误解和低估.
90年前,俄罗斯物理学家弗里德曼(1888—1925)首次阐述了爱因斯坦的广义相对论存在非静态的解.他发现这些解可以描述宇宙的膨胀、收缩、坍缩,甚至可能从奇点中诞生. 相似文献
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一、高频引力波不能使用传统方法进行探测根据广义相对论的预言,利用引力波的潮汐效应,可以对引力波进行探测。最早的引力波探测方法是共振质量法,其典型装置除韦伯棒(WeberBar)外,还有ALLEGRO(美国)、EXPLORER(意大利)等。它们的共同特点是将棒状或球状质量作为引力波的耦合天线,如果天线接收到了引力波信号,则天线上的不同部分之间将发生伸缩效应,利用声电转换(比如压电效应)可以将机械振动转换成电信号,测量电信号就可以确认是否探测到了引力波信号;这一类引力波探测装置对引力波共振的频率一般为102104Hz. 相似文献
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文章简单介绍了标准(大爆炸)宇宙模型的成功和困难,着重介绍了暴涨宇宙学的研究历史和最近的进展,并展望了今后人们可能的关注方向 相似文献
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High-frequency gravitational waves having large spectral densities and their electromagnetic response 下载免费PDF全文
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. 相似文献
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Extremely powerful astrophysical electromagnetic(EM) systems could be possible sources of highfrequency gravitational waves(HFGWs). Here, based on properties of magnetars and gamma-ray bursts(GRBs), we address "Gamma-HFGWs"(with very high-frequency around 10~(20) Hz) caused by ultra-strong EM radiation(in the radiation-dominated phase of GRB fireballs) interacting with super-high magnetar surface magnetic fields(~10~(11) T).By certain parameters of distance and power, the Gamma-HFGWs would have far field energy density ?gw around10~(-6), and they would cause perturbed signal EM waves of~10~(-20) W/m~2 in a proposed HFGW detection system based on the EM response to GWs. Specially, Gamma-HFGWs would possess distinctive envelopes with characteristic shapes depending on the particular structures of surface magnetic fields of magnetars, which could be exclusive features helpful to distinguish them from background noise. Results obtained suggest that magnetars could be involved in possible astrophysical EM sources of GWs in the very high-frequency band, and Gamma-HFGWs could be potential targets for observations in the future. 相似文献
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The process of primordial black hole (PBH) formation is inevitably accompanied by scalar induced gravitational waves (SIGWs). The strong correlation between PBH and SIGW signals may offer a promising approach to detecting PBHs in upcoming gravitational wave experiments, such as the Laser Interferometer Space Antenna (LISA). We investigate third order SIGWs during a radiation-dominated era in the case of the monochromatic primordial power spectrum \begin{document}$ \mathcal{P}_{\zeta}=A_{\zeta}k_*\delta\left(k-k_*\right) $\end{document} ![]()
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. For LISA observations, the relationships between the signal-to-noise ratio (SNR) and monochromatic primordial power spectrum are studied systematically, revealing that the effects of third order SIGWs extend the cutoff frequency from \begin{document}$ 2f_* $\end{document} ![]()
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to \begin{document}$ 3f_* $\end{document} ![]()
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and lead to an approximately 200% increase in the SNR for the frequency band from \begin{document}$ 10^{-5} $\end{document} ![]()
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Hz to \begin{document}$ 1.6\times 10^{-3} $\end{document} ![]()
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Hz, corresponding to PBHs with masses in the range \begin{document}$4\times 10^{-12}M_{\odot} \sim 10^{-7}M_{\odot}$\end{document} ![]()
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. We find that there is a critical value, \begin{document}$ A_*=1.76\times 10^{-2} $\end{document} ![]()
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, for the amplitude of the monochromatic primordial power spectra, such that when \begin{document}$ A_{\zeta}>A_* $\end{document} ![]()
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, the energy density of third order SIGWs is larger than that of second order SIGWs. 相似文献
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Takashi Nakamura 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2006,82(9):311-327
Numerical simulations were performed for the formation process of rotating black holes. It is suggested that Kerr black holes are formed for wide ranges of initial parameters. The nature of gravitational waves from a test particle falling into a Kerr black hole as well as the development of 3D numerical relativity for the coalescing binary neutron stars are discussed. 相似文献
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20世纪建立起的宇宙大爆炸模型取得了巨大的成功,但仍期待着新的革命性的突破。探知宇宙起源及其演化是新世纪对全世界科学家的新挑战,其重要性在近期公布的中国“十三五”规划纲要中得到了高度的肯定。现代宇宙学理论,暴胀以及非奇异宇宙模型如反弹等,预言了原初引力波的存在,但至今还没有被实验证实。不同于近期LIGO合作组探测到的黑洞引力波,原初引力波是宇宙诞生时期产生的,携带着丰富的宇宙学信息,是引力波探测的全新波段,是引力波探测的下一个突破方向。文章简述了中国的阿里原初引力波实验计划及相关的科学问题。 相似文献
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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 相似文献
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The imprints of the neutron star crust on the gravitational waves emitted from the axial w-modes are investigated by adopting two typical equations of state (EOSs) of the crust matter and two representative EOSs of the core matter. It is shown that there is a significant effect of the crust EOSs on the gravitational waves from the axial w-mode oscillation for a stiff core EOS. 相似文献