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[en] The RareNoise project investigates non-equilibrium effects in gravitational wave detectors. We illustrate the physics behind the project and the planned project development, involving experimental, numerical and theoretical research.
[en] We describe a Laser Gravitational-wave Antenna in Geodic Orbit design called LAGRANGE that maintains all important LISA science at about half the cost of the original LISA mission and with reduced technical risk. It consists of 3 drag-free spacecraft (SC) in a geocentric formation. Fixed antennas allow continuous contact with the Earth, solving the problem of communications bandwidth and latency. A 70 mm diameter sphere with a 35 mm gap to its enclosure serves as the single inertial reference per SC, operating in 'true' drag-free mode (no test mass forcing). Other advantages are: a single caging design based on the DISCOS 1972 drag-free mission, an all optical read-out with pm fine and nm coarse sensors, and the extreme technology heritage from the Honeywell gyroscopes, and the DISCOS and Gravity Probe B drag-free sensors. An interferometric Measurement System, designed with reflective optics and a highly stabilized frequency standard, performs the ranging between test masses and requires a single optical bench with one laser per SC. Two 20 cm diameter telescope per SC, each with infield pointing, incorporate novel technology developed for advanced optical systems by Lockheed Martin, who also designed the SC based on a multi-flight proven bus structure. Additional technological advancements include include updated propulsion technology, improved thermal control, and a UV-LED charge management system. LAGRANGE subsystems are designed to be scalable and modular, making them interchangeable with those of LISA or other gravitational science missions. We plan to space qualify critical technologies on small and nano satellite flights, with the first launch (UV-LED Sat) in 2013. We further propose a relaxed performance version of LAGRANGE to be flown before 2020 at one quarter the cost of LISA. The requirements on the drag-free sensors and interferometers are relaxed by factors of 10-100 while the core science, super massive black hole (MBH) mergers, is maintained. (authors)
[en] A brief survey of peculiarities of physical processes, used in the development of a gravitational radiator and a gravitational detector, is presented. The methods of radiation of gravitational waves under laboratory conditions are conventionally divided into two classes: radiators with spontaneous generation of gravitational waves and those of a parametric type. Some propositions on reception techniques of gravitational waves are considered. As applied to the problem solution of development of the radiator+detector laboratory gravitational scheme great hopes concerning the detector design are related to the mechanism of wave transformation. 10 refs
[en] The authors show that for any kind of detector the best way to search for a ''bursts with memory'' (BWM) gravitation wave is to integrate up the signal for an integration time tau-circumflex approx.= 1/fsub(opt), where fsub(opt) is the frequency at which the detector has optimal amplitude sensitivity to ordinary bursts (bursts with memory). In such a search the sensitivity to BWM with duration Δt < or approx. 1/fsub(opt) is independent of the burst duration Δt and is approximately equal to the sensitivity to ordinary bursts one cycle long with frequency fsub(opt). (author)
[en] Noise of non-astrophysical origin contaminates science data taken by the Advanced Laser Interferometer Gravitational-wave Observatory and Advanced Virgo gravitational-wave detectors. Characterization of instrumental and environmental noise transients has proven critical in identifying false positives in the first a LIGO observing run O1. In this talk, we present three algorithms designed for the automatic classification of non-astrophysical transients in advanced detectors. Principal Component Analysis for Transients (PCAT) and an adaptation of LAL Inference Burst (PC-LIB) are based on Principal Component Analysis. The third algorithm is a combination of a glitch finder called Wavelet Detection Filter (WDF) and unsupervised machine learning techniques for classification.
[en] The LIGO Scientific Collaboration recently reported a new upper limit on an isotropic stochastic background of gravitational waves obtained based on the data from the third LIGO science run (S3). Here I present a new method for obtaining directional upper limits on stochastic gravitational waves that essentially implements a gravitational wave radiometer. The LIGO Scientific Collaboration intends to use this method for future LIGO science runs
[en] The cleaning procedure used to produce the data that we analyze for the search of periodic sources of gravitational waves is based on different steps, which are applied to both time and frequency domain data. We have recently improved the procedure, which now consists of different steps. The use of a cleaned procedure is in principle important, since it is aimed to recover at best the observation time from the data by vetoing only times where disturbances act and not entire data chunks. Clearly, the effect of the procedure depends on the nature of the data, and is thus highly related to the detector characteristics in a particular run. We will here describe the whole cleaning chain, by giving details and examples based on the C7 and WSR10 Virgo runs.
[en] We propose the use of heralded photons to detect Gravitational Waves (G Ws). Heralded photons are those photons that, produced during a parametric down conversion process, are labelled by the detection and counting of coincidences of their correlated or entangled twins and therefore can be discriminated from the background noise, independently of the type of correlation/entanglement used in the set-up. Without losing any generality, we illustrate our proposal with a 'gedankenexperiment', in which the presence of a gravitational wave causes a relative rotation of the reference frames associated to the double-slit and the test polarizer, respectively, of a Walborn quantum eraser. In this thought experiment, the GW is revealed by the detection of heralded photons in the dark fringes of the recovered interference pattern by the quantum eraser. Other types of entanglement, such as momentum-space or energy-time, could be used to obtain heralded photons to be used in the future with high-frequency GW interferometric detectors when enough bright sources of correlated photons will be available.
[en] Modern methods of detection of gravitational waves of cosmic origin are presented in a popular form. A brief description is given of surface aerials on the base of aluminium and sapphire resonators and of possible satellite aerials. It is indicated that the found decrease of the revolution period of one of the binary stellar systems with pulsar may be an indirect confirmation of the gravitational wave existance