Earth-orbiting low-frequency gravitational wave detector

We propose a new method of gravitational wave detection in the 10^–1÷ 10^–2Hz band for a space laboratory based on the use of the Kozorez effect in the magnetic interaction of superconducting solenoids.     

Sensitivity of the heterodyne gravitational wave detector

In order to explore the actual astrophysical possibilities of the heterodyne gravitational wave detector we study its main limitation, due to the motion around the Earth and the Sun. This places an intrinsic limit to the time during which the detector stays tuned to the source and prevents us from taking full advantage of the very large quality factor of sources like pulsars. We study the ratio of signal to thermal noise and find, for a wave of given amplitude, that it is proportional to ^4/3 Q ^1/2, where is the frequency of the source andQ the mechanical quality factor. Consideration of possible astrophysical sources shows the difficulty of detection and points to the need for a tunable heterodyne system.     

Enhanced sensitivity of a gravitational wave detector

We calculate the change in energy absorbed and the power spectrum in a coherently driven antenna induced by interaction with gravitational radiation. The coherent driving field prepares the antenna in a correlated state which enhances the sensitivity of the detector as proposed in a recent paper by Weber.     

Optical detector topology for third-generation gravitational wave observatories

The third generation of gravitational wave observatories, with the aim of providing 100 times better sensitivity than currently operating interferometers, is expected to establish the evolving field of gravitational wave astronomy. A key element, required to achieve this ambitious sensitivity goal, is the exploration of new interferometer geometries, topologies and configurations. In this article we review the current status of the ongoing design work for third-generation gravitational wave observatories. The main focus is the evaluation of the detector geometry and detector topology. In addition we discuss some promising detector configurations and potential noise reduction schemes.     

Propagation effect of gravitational wave on detector response

正Dear Editors,The detection of gravitational waves(GW)in the event GW150914 by the two advanced detectors of the Laser Interferometer Gravitational-wave Observatory(LIGO)[1]opens a new era for the direct detection of GW[2],searching black hole coalescence[3]and‘heavy’black holes with more than25 solar mass[4],test of general relativity[5],understanding the astrophysical environment of black hole formation[6],etc.In one words,the era of multi-messenger astronomy has     

Signal processing in a Dulkyn gravitational wave detector

We consider a system for stabilization of the phase, correlation self-compensation of noise, and optimal processing of the response signal in a Dulkyn laser pentagonal gravitational-wave detector, providing noise detection and optimal processing of the PSR J1537 + 1155 response signal in the laser pentagonal detector. Kazan State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 22–28, February, 1998.     

Remark on a toroidal detector of a gravitational wave

The object of this paper is to review the detector of a gravitational wave that was proposed by Braginsky and Mensky (1971). The derivation of the sensitivity is based on the same assumption as they proposed. It is concluded that the phase difference is linear in time and that the sensitivity of this detector is different from the result claimed by Braginsky and Mensky. The foundation to obtain the phase difference, i.e., the sensitivity, in this paper is not the frequency as they used but rather the movement of the wave front in the detector.     

Astrophysics from data analysis of spherical gravitational wave detectors

The direct detection of gravitational waves will provide valuable astrophysical information about many celestial objects. Also, it will be an important test to general relativity and other theories of gravitation. The gravitational wave detector SCHENBERG has recently undergone its first test run. It is expected to have its first scientific run soon. In this work the data analysis system of this spherical, resonant mass detector is tested through the simulation of the detection of gravitational waves generated during the inspiralling phase of a binary system. It is shown from the simulated data that it is not necessary to have all six transducers operational in order to determine the source’s direction and the wave’s amplitudes.     

A proposed back action evading read-out for a gravitational wave detector

We propose a Back Action Evasion read out to improve the sensitivity of a capacitively coupled resonant transducer for gravitational wave detectors. We show that the noise can be reduced by factors 10 to 100 over the standard amplifier limit using detector parameters already achieved.     

EOM sideband phase characteristics for the spaceborne gravitational wave detector LISA

The Laser Interferometer Space Antenna (LISA) is a joint ESA/NASA mission proposed to observe gravitational waves. One important noise source in the LISA phase measurement will be on-board reference oscillators. An inter-spacecraft clock tone transfer chain will be necessary to remove this non-negligible phase noise in post processing. One of the primary components of this chain are electro-optic modulators (EOMs). At modulation frequencies of 2 GHz, we characterise the excess phase noise of a fibre-coupled integrated EOM in the LISA measurement band (0.1 mHz to 1 Hz). The upper phase noise limit was found to be almost an order of magnitude better than required by the LISA mission. In addition, the EOM’s phase dependence on temperature and optical power was determined. The measured coefficients are within a few milliradians per kelvin and per watt respectively and thereby negligible with the expected on-board temperature and laser power stability.     

A photon pressure calibrator for the GEO 600 gravitational wave detector

Interferometer mirror displacement induced by radiation pressure is used to demonstrate an alternative calibration method for the GEO 600 detector. The photon calibrator utilizes an amplitude modulated laser diode with up to 1.4 W output power at a wavelength of 1035 nm. The achieved accuracy of the strain amplitude calibration is dominated by the laser power calibration error, which is in the range of ±4% for the measurements presented in this Letter.     

Reduction of thermal fluctuations in a cryogenic laser interferometric gravitational wave detector

The thermal fluctuation of mirror surfaces is the fundamental limitation for interferometric gravitational wave (GW) detectors. Here, we experimentally demonstrate for the first time a reduction in a mirror's thermal fluctuation in a GW detector with sapphire mirrors from the Cryogenic Laser Interferometer Observatory at 17 and 18 K. The detector sensitivity, which was limited by the mirror's thermal fluctuation at room temperature, was improved in the frequency range of 90 to 240 Hz by cooling the mirrors. The improved sensitivity reached a maximum of 2.2×10(-19) m/√Hz at 165 Hz.     

Nonclosed spherical gravitational sources

The general solution of Einstein's equations governing the behavior of a nonclosed spherical gravitational source exchanging the mass-energy with its environment is investigated and an exterior solution concerning the emission and accretion in some special cases is found. Also the transfer of mass-energy inside the horizon is briefly discussed.     

Excess noise in the steel suspension wires for the laser gravitational wave detector

Progress in the research in mechanical excess noise is reported. An improved technique for wire oscillation measurement has been applied to the investigation of the suspension of a test mass for a GW detector. The dependence of the excess noise intensity in the fundamental violin mode of the steel wires on the stress value is obtained.     

Stochastic gravitational wave background due to gravitational wave memory

Gravitational wave memory is an important prediction of general relativity, which has not been detected yet. Amounts of memory events can form a stochastic gravitational wave memory background. Here we find that memory background can be described as a Brownian motion in the condition that the observation time is longer than the averaged time interval between two successive memory events. We investigate, for the first time, the memory background of binary black hole coalescences. We only consider...     

Electromagnetic detector for gravitational waves

We analyze the mode of operation of a two-level parametric electromagnetic detector for gravitational waves which is tunable and potentially more sensitive than the mechanical antennas currently considered.