LIGO Experiments Cannot Detect Gravitational Waves by Using Laser Michelson Interferometers—Light’s Wavelength and Speed Change Simultaneously When Gravitational Waves Exist Which Make the Detections of Gravitational Waves Impossible for LIGO Experiments

It is proved strictly based on general relativity that two important factors are neglected in LIGO experiments by using Michelson interferometers so that fatal mistakes were caused. One is that the gravitational wave changes the wavelength of light. Another is that light’s speed is not a constant when gravitational waves exist. According to general relativity, gravitational wave affects spatial distance, so it also affects the wavelength of light synchronously. By considering this fact, the phase differences of lasers were invariable when gravitational waves passed through Michelson interferometers. In addition, when gravitational waves exist, the spatial part of metric changes but the time part of metric is unchanged. In this way, light’s speed is not a constant. When the calculation method of time difference is used in LIGO experiments, the phase shift of interference fringes is still zero. So the design principle of LIGO experiment is wrong. It was impossible for LIGO to detect gravitational wave by using Michelson interferometers. Because light’s speed is not a constant, the signals of LIGO experiments become mismatching. It means that these signals are noises actually, caused by occasional reasons, no gravitational waves are detected really. In fact, in the history of physics, Michelson and Morley tried to find the absolute motion of the earth by using Michelson interferometers but failed at last. The basic principle of LIGO experiment is the same as that of Michelson-Morley experiment in which the phases of lights were invariable. Only zero result can be obtained, so LIGO experiments are destined failed to find gravitational waves.

Decoupling Algorithms for the Gravitational Wave Spacecraft

The gravitational wave spacecraft is a complex multi-input multi-output dynamic system.The gravitational wave detection mission requires the spacecraft to achieve single spacecraft with two laser links and high-precision control.Establishing one spacecraftwith two laser links,compared to one spacecraft with a single laser link,requires an upgraded decoupling algorithmfor the link establishment.The decoupling algorithmwe designed reassigns the degrees of freedomand forces in the control loop to ensure sufficient degrees of freedomfor optical axis control.In addressing the distinct dynamic characteristics of different degrees of freedom,a transfer function compensation method is used in the decoupling process to further minimize motion coupling.The open-loop frequency response of the systemis obtained through simulation.The upgraded decoupling algorithms effectively reduce the open-loop frequency response by 30 dB.The transfer function compensation method efficiently suppresses the coupling of low-frequency noise.

Fault diagnosis method of link control system for gravitational wave detection

To maintain the stability of the inter-satellite link for gravitational wave detection,an intelligent learning monitoring and fast warning method of the inter-satellite link control system failure is proposed.Different from the traditional fault diagnosis optimization algorithms,the fault intelligent learning method pro-posed in this paper is able to quickly identify the faults of inter-satellite link control system despite the existence of strong cou-pling nonlinearity.By constructing a two-layer learning network,the method enables efficient joint diagnosis of fault areas and fault parameters.The simulation results show that the average identification time of the system fault area and fault parameters is 0.27 s,and the fault diagnosis efficiency is improved by 99.8%compared with the traditional algorithm.

The Three-Arm Michelson-Fabry-Perot Detector for Gravitational Waves

A three-arm Michelson-Fabry-Perot detector for gravitational waves is designed. It consists of three Michelson Fabry-Perot interferometers, one for each pair of arms. The new detector can be used to confirm whether the gravitational waves are in general relativity polarization states and to set the strong constraints on non-GR gravitational wave polarization states. By the new detectors, the angular resolution of sources can be improved significantly. With the new detector, it is easier to search for and confirm a gravitational wave signal in the observation data.

Past,present and future of the Resonant-Mass gravitational wave detectors

Resonant-mass gravitational wave detectors are reviewed from the concept of gravitational waves and its mathematical derivation, using Einstein＇s general relativity, to the present status of bars and spherical detectors, and their prospects for the future, which include dual detectors and spheres with non-resonant transducers. The review not only covers technical aspects of detectors and sciences that will be done, but also analyzes the subject in a historical perspective, covering the various detection efforts over four decades, starting from Weber＇s pioneering work.

Sensitivity function analysis of gravitational wave detection with single-laser and large-momentum-transfer atomic sensors

Recently, a configuration using atomic interferometers （AIs） had been sug- gested for the detection of gravitational waves. A new AI with some additional laser pulses for implementing large momentum transfer was also put forward, in order to reduce the effect of shot noise and laser frequency noise. We use a sensitivity function to analyze all possible configurations of the new AI and to distinguish how many mo- menta are transferred in a specific configuration. By analyzing the new configuration, we further explore a detection scheme for gravitational waves, in particular, that ame- liorates laser frequency noise. We find that the amelioration occurs in such a scheme, but novelly, in some cases, the frequency noise can be canceled completely by using a proper data processing method.

On Gravitational Waves: Did We Simply Detect the Gravitational Effect of the Sun on the Photons Moving in the Cavity of Interferometers LIGO and VIRGO?

On September 14, 2015 09:50:45 UTC, the two laser interferometers of the LIGO program simultaneously observed a first gravitational wave signal called GW150914. With the commissioning of the VIRGO interferometer in 2017, two other detections, GW170814 and GW170817, were observed and their positions given accurately by LIGO and VIRGO. In this article, I argue that the photons circulating in the cavities of the three interferometers of LIGO and VIRGO were sensitive to the field of attraction of the planets of our Solar System and more particularly to that of the Sun, and would not be due to a coalescence of black hole or neutron stars. The shape of the signals obtained by my interaction model (called GEAR) between the photons in the interferometer cavity and the gravitational field of the Sun is very similar to that of a compact binary coalescence, identical to those obtained by general relativity. Solving the equations of GEAR also gives the exact positions and pseudo-date of the coalescences of all the LIGO and VIRGO detections detected so far, and probably those that will come at the end of 2018 and beyond.

Estimation of spectrum and parameters of relic gravitational waves using space-borne interferometers

We present a study of spectrum estimation of relic gravitational waves(RGWs) as a Gaussian stochastic background from output signals of future space-borne interferometers, like LISA and ASTROD.As the target of detection, the analytical spectrum of RGWs generated during inflation is described by three parameters: the tensor-scalar ratio, the spectral index and the running index. The Michelson interferometer is shown to have a better sensitivity than Sagnac and symmetrized Sagnac. For RGW detection, we analyze the auto-correlated signals for a single interferometer, and the cross-correlated, integrated as well as unintegrated signals for a pair of interferometers, and give the signal-to-noise ratio(SNR) for RGW, and obtain lower limits of the RGW parameters that can be detected. By suppressing noise level, a pair has a sensitivity2 orders better than a single for one year observation. SNR of LISA will be 4–5 orders higher than that of Advanced LIGO for the default RGW. To estimate the spectrum, we adopt the maximum likelihood(ML)estimation, calculate the mean and covariance of signals, obtain the Gaussian probability density function(PDF) and the likelihood function, and derive expressions for the Fisher matrix and the equation of the ML estimate for the spectrum. The Newton-Raphson method is used to solve the equation by iteration. When the noise is dominantly large, a single LISA is not effective for estimating the RGW spectrum as the actual noise in signals is not known accurately. For cross-correlating a pair, the spectrum cannot be estimated from the integrated output signals either, and only one parameter can be estimated with the other two being either fixed or marginalized. We use the ensemble averaging method to estimate the RGW spectrum from the un-integrated output signals. We also adopt a correlation of un-integrated signals to estimate the spectrum and three parameters of RGW in a Bayesian approach. For all three methods, we provide simulations to illustrate their feasibility.

Estimation of far-field wavefront error of tilt-to-length distortion coupling in space-based gravitational wave detection

In space-based gravitational wave detection, the estimation of far-field wavefront error of the distorted beam is the precondition for the noise reduction. Zernike polynomials are used to describe the wavefront error of the transmitted distorted beam. The propagation of a laser beam between two telescope apertures is calculated numerically. Far-field wavefront error is estimated with the absolute height of the peak-to-valley phase deviation between the distorted Gaussian beam and a reference distortion-free Gaussian beam. The results show that the pointing jitter is strongly related to the wavefront error. Furthermore, when the jitter decreases 10 times from 100 nrad to 10 nrad, the wavefront error reduces for more than an order of magnitude. In the analysis of multi-parameter minimization, the minimum of wavefront error tends to Z[5,3] Zernike in some parameter ranges. Some Zernikes have a strong correlation with the wavefront error of the received beam. When the aperture diameter increases at Z[5,3] Zernike, the wavefront error is not monotonic and has oscillation.Nevertheless, the wavefront error almost remains constant with the arm length increasing from 10-1Mkm to 10~3Mkm.When the arm length decreases for three orders of magnitude from 10-1Mkm to 10-4Mkm, the wavefront error has only an order of magnitude increasing. In the range of 10-4Mkm to 10~3Mkm, the lowest limit of the wavefront error is from 0.5 fm to 0.015 fm at Z[5,3] Zernike and 10 nrad jitter.

Detecting Very-High-Frequency Relic Gravitational Waves by a Waveguide

The polarization vector （PV） of an electromagnetic wave （EW） will experience a rotation in a region of spacetime perturbed by gravitational waves （GWs）. Based on this consideration, Cruise＇s group has built an annular waveguide to detect GWs. We give detailed calculations of the rotations of polarization vector of an EW caused by incident GWs from various directions and in various polarization states, and then analyze the accumulative effects on the polarization vector when the EW passes n cycles along the annular waveguide. We reexamine the feasibility and limitation of this method to detect GWs of high frequency around 100 MHz, in particular the relic gravitational waves （RGWs）. By comparing the spectrum of RGWs in the accelerating universe with the detector sensitivity of the current waveguide, it is found that the amplitude of the RGWs is too low to be detected by the waveguide detectors currently operating. Possible ways of improvements on detection are suggested.

Did LIGO Really Detect Gravitational Waves?—The Existence of Electromagnetic Interaction Made the Experiments of LIGO Invalid

The paper proves that due to the existence of electromagnetic interaction, the experiments of LIGO cannot detect gravitational waves. This is also the reason why Weber’s experiments of gravitational waves failed. In fact, the formulas of general relativity that gravitational waves affect distances are only suitable for particles in vacuum. LIGO experiments are carried out on the earth. The laser interferometers are fixed on the steel pipes on the earth’s surface in the balanced state of electromagnetic force. Electromagnetic force is 1040 times greater than gravity. Gravitational waves are too weak to overcome electromagnetic force and change the length of steel pipes. Without considering this factor, the design principle of LIGO experiment has serious problem. The experiments to detect gravitational waves should move to space to avoid the influence of electromagnetic interaction. Besides, LIGO experiments have the following problems. 1) No explosion source of gravitational waves is really founded. 2) The argument that the Einstein’s theory of gravity is verified is a vicious circle and invalid in logic. 3) The results of experiments cause sharp contradiction for the energy currents of gravitational waves. The difference reaches to 1024 times and is unacceptable. 4) The method of numerical relativity causes great errors due to the existence of singularities. The errors are enlarged by the effect of butterfly due to the non-linearity of Einstein’s equation of gravity. 5) The so-called change of length 10-18 m between two glasses of interferometers detected in the experiment exceeds the ability of current technique. This kind of precise has entered micro-scalar. The uncertain principle of quantum mechanics makes it impossible. The signs appeared in LIGO experiments are not caused by distance change. 6) LIGO experiments have not detected gravitational waves. What detected may be the signs of disturbances coming from the middle region between two laser interferometers.

Was LIGO’s Gravitational Wave Detection a False Alarm?

This article presents a new type of whitening filter (allowing the “passing” of some noise sources) applied to process the data recorded in LIGO’s GW150914 and GW151226 events. This new analysis shows that in the GW150914 event, the signals from the collision of two black holes are very similar to the 32.5 Hz noise sources observed in both of LIGO’s detectors. It also points out that these 32.5 Hz noise sources are powered by a 30 Hz sub harmonic, coming from the 60 Hz power system. In the GW1226 event, the same analysis points out that the NR template is very similar to the 120 Hz noise source. Therefore, the signals recorded in these events were probably generated by some small changes with the 60 Hz frequency in the US power grid. This can be caused, for example, by a power variation in the DC link, which can appear in both detectors in the same 10 ms time window. As this kind of power grid occurrence did not change the voltage levels, it may have gone unnoticed by LIGO’s electrical power supply’s monitoring system.

Gravitational Waves: Present Status and Future Prospectus

Remarkable progress has been made during recent years on the development of gravitational wave detectors. The review describes the present status and future prospectus of the gravitational wave astronomy. The main theme is to review the prominent long baseline detectors in operation around the world and proposed baseline and space-borne interferometers. Looking to the future, the major upgrades to the ground based detectors and new planned detectors will be completed over the coming years, which will create a network of detectors with the significantly improved sensitivity required to detect gravitational waves. Beyond this, the concept and design of possible future “third generation” gravitational-wave detectors will be discussed. Sources such as coalescing compact binary systems, neutron stars in low-mass X-ray binaries, stellar collapses and pulsars are all possible candidates for detection.

Numerical simulations of the wavefront distortion of inter-spacecraft laser beams caused by solar wind and magnetospheric plasmas

Plasma turbulence may lead to additional wavefront distortion of inter-spacecraft laser beams during the operation of spaceborne gravitational wave(GW)observatories,e.g.Tian Qin.By making use of the Space Weather Modelling Framework(SWMF)model and realistic orbit data for the Tian Qin constellation,the characteristic parameters of the plasma turbulence present at the Tian Qin orbit are obtained.As a first step,this work is based on the assumptions that the cold plasma approximation is valid and that the effects of the electromagnetic field induced by charge separation within the Debye length on the laser's wavefront can be ignored.An atmospheric turbulence-laser interaction model is then applied to analyze the effects of the plasma turbulence on the inter-spacecraft laser's wavefront.The preliminary results show that the wavefront distortion caused by the plasma turbulence is 10^-9 rad,which is significantly less than the designated error budget,i.e.10^-6 rad,and thus will not affect the laser interferometry.

Analysis and suppression of thermal effect of an ultra-stable laser interferometer for space-based gravitational waves detection

In this paper,we present a suppression method for the thermal drift of an ultra-stable laser interferometer.The detailed analysis on the Michelson interferometer indicates that the change in optical path length induced by temperature variation can be effectively reduced by choosing proper thickness and/or incident angle of a compensator.Taking the optical bench of the Laser Interferometer Space Antenna Pathfinder as an example,we analyze the optical bench model with a compensator and show that the temperature coefficient of this laser interferometer can be reduced down to 1 pm/K with an incident angle of 0.267828 rad.The method presented in this paper can be used in the design of ultra-stable laser interferometers,especially for space-based gravitational waves detection.

Near real-time gravitational wave data analysis of the massive black hole binary with TianQin

Space-borne gravitational wave(GW)detectors can detect the merger of massive black holes.The early warning and localization of GW events before merging can be used to inform electromagnetic telescopes and conduct multimessenger observations.However,this requires real-time data transmission and analysis capabilities.The geocentric orbit of the space-borne GW detector Tian Qin makes it possible to conduct real-time data transmission.In this study,we develop a search and localization pipeline for massive black hole binaries(MBHBs)with Tian Qin under both regular and real-time data transmission modes.We demonstrate that,with real-time data transmission,MBHBs can be accurately localized on the fly.With the approaching merger,each analysis can be finished in only 40 min.For an MBHB system at a distance of 1 Gpc,if we receive data every hour,then we can pinpoint its location to within less than 1 deg^(2)on the final day before the merger.

Technology for the next gravitational wave detectors

This paper reviews some of the key enabling technologies for advanced and future laser interferometer gravitational wave detectors, which must combine test masses with the lowest possible optical and acoustic losses, with high stability lasers and various techniques for suppressing noise. Sect. 1 of this paper presents a review of the acoustic properties of test masses. Sect. 2 reviews the technology of the amorphous dielectric coatings which are currently universally used for the mirrors in advanced laser interferometers, but for which lower acoustic loss would be very advantageous. In sect. 3 a new generation of crystalline optical coatings that offer a substantial reduction in thermal noise is reviewed. The optical properties of test masses are reviewed in sect. 4, with special focus on the properties of silicon, an important candidate material for future detectors. Sect. 5 of this paper presents the very low noise, high stability laser technology that underpins all advanced and next generation laser interferometers.

The next detectors for gravitational wave astronomy

This paper focuses on the next detectors for gravitational wave astronomy which will be required after the current ground based detectors have completed their initial observations, and probably achieved the first direct detection of gravitational waves. The next detectors will need to have greater sensitivity, while also enabling the world array of detectors to have improved angular resolution to allow localisation of signal sources. Sect. 1 of this paper begins by reviewing proposals for the next ground based detectors,and presents an analysis of the sensitivity of an 8 km armlength detector, which is proposed as a safe and cost-effective means to attain a 4-fold improvement in sensitivity. The scientific benefits of creating a pair of such detectors in China and Australia is emphasised. Sect. 2 of this paper discusses the high performance suspension systems for test masses that will be an essential component for future detectors, while sect. 3 discusses solutions to the problem of Newtonian noise which arise from fluctuations in gravity gradient forces acting on test masses. Such gravitational perturbations cannot be shielded, and set limits to low frequency sensitivity unless measured and suppressed. Sects. 4 and 5 address critical operational technologies that will be ongoing issues in future detectors. Sect. 4 addresses the design of thermal compensation systems needed in all high optical power interferometers operating at room temperature. Parametric instability control is addressed in sect. 5. Only recently proven to occur in Advanced LIGO, parametric instability phenomenon brings both risks and opportunities for future detectors. The path to future enhancements of detectors will come from quantum measurement technologies. Sect. 6 focuses on the use of optomechanical devices for obtaining enhanced sensitivity, while sect. 7 reviews a range of quantum measurement options.

Gravitational wave astronomy: the current status

In the centenary year of Einstein's General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Sect. 1 of this paper reviews the historical development of gravitational wave astronomy from Einstein's first prediction to our current understanding the spectrum. It is shown that detection of signals in the audio frequency spectrum can be expected very soon, and that a north-south pair of next generation detectors would provide large scientific benefits. Sect. 2 reviews the theory of gravitational waves and the principles of detection using laser interferometry. The state of the art Advanced LIGO detectors are then described. These detectors have a high chance of detecting the first events in the near future. Sect. 3 reviews the KAGRA detector currently under development in Japan,which will be the first laser interferometer detector to use cryogenic test masses. Sect. 4 of this paper reviews gravitational wave detection in the nanohertz frequency band using the technique of pulsar timing. Sect. 5 reviews the status of gravitational wave detection in the attohertz frequency band, detectable in the polarisation of the cosmic microwave background, and discusses the prospects for detection of primordial waves from the big bang. The techniques described in sects. 1–5 have already placed significant limits on the strength of gravitational wave sources. Sects. 6 and 7 review ambitious plans for future space based gravitational wave detectors in the millihertz frequency band. Sect. 6 presents a roadmap for development of space based gravitational wave detectors by China while sect. 7 discusses a key enabling technology for space interferometry known as time delay interferometry.

Signal photon flux generated by high-frequency relic gravitational waves

The power spectrum of primordial tensor perturbations Pt increases rapidly in the high frequency region if the spectral index nt 〉 0. It is shown that the amplitude of relic gravitational waves ht （5×109 Hz） varies from 10-36 to 10-25 while rtt varies from -6.25 × 10-3 to 0.87. A high frequency gravitational wave detector proposed by F,-Y, Li detects gravitational waves through observing the perturbed photon flux that is generated by interaction between relic gravitational waves and electromagnetic field. It is shown that the perturbative photon flux N1x （5 × 109 Hz） varies from 1.40× 10-4 s-i to 2.85× 107 s-i while nt varies from -6.25 ×10-3 to 0.87, Correspondingly, the ratio of the transverse perturbative photon flux N1x to the background photon flux varies from 10-28 to 10-16.