We present an up-to-date, comprehensive summary of the rates for all types of compact binary coalescence sources detectable by the initial and advanced versions of the ground-based gravitational-wave detectors LIGO and Virgo. Astrophysical estimates for compact-binary coalescence rates depend on a number of assumptions and unknown model parameters and are still uncertain. The most confident among these estimates are the rate predictions for coalescing binary neutron stars which are based on extrapolations from observed binary pulsars in our galaxy. These yield a likely coalescence rate of 100 Myr−1 per Milky Way Equivalent Galaxy (MWEG), although the rate could plausibly range from 1 Myr−1 MWEG−1 to 1000 Myr−1 MWEG−1 (Kalogera et al 2004 Astrophys. J. 601 L179; Kalogera et al 2004 Astrophys. J. 614 L137 (erratum)). We convert coalescence rates into detection rates based on data from the LIGO S5 and Virgo VSR2 science runs and projected sensitivities for our advanced detectors. Using the detector sensitivities derived from these data, we find a likely detection rate of 0.02 per year for Initial LIGO–Virgo interferometers, with a plausible range between 2 × 10−4 and 0.2 per year. The likely binary neutron–star detection rate for the Advanced LIGO–Virgo network increases to 40 events per year, with a range between 0.4 and 400 per year.

Advanced gravitational wave interferometers, currently under realization, will soon permit the detection of gravitational waves from astronomical sources. To open the era of precision gravitational wave astronomy, a further substantial improvement in sensitivity is required. The future space-based Laser Interferometer Space Antenna and the third-generation ground-based observatory Einstein Telescope (ET) promise to achieve the required sensitivity improvements in frequency ranges. The vastly improved sensitivity of the third generation of gravitational wave observatories could permit detailed measurements of the sources' physical parameters and could complement, in a multi-messenger approach, the observation of signals emitted by cosmological sources obtained through other kinds of telescopes. This paper describes the progress of the ET project which is currently in its design study phase.

Advanced gravitational wave detectors, currently under construction, are expected to directly observe gravitational wave signals of astrophysical origin. The Einstein Telescope (ET), a third-generation gravitational wave detector, has been proposed in order to fully open up the emerging field of gravitational wave astronomy. In this paper we describe sensitivity models for ET and investigate potential limits imposed by fundamental noise sources. A special focus is set on evaluating the frequency band below 10 Hz where a complex

Abstract. The advanced interferometer network will herald a new era in observational astronomy. There is a very strong science case to go beyond the advanced detector network and build detectors that operate in a frequency range from 1 Hz-10 kHz, with sensitivity a factor ten better in amplitude. Such detectors will be able to probe a range of topics in nuclear physics, astronomy, cosmology and fundamental physics, providing insights into many unsolved problems in these areas.PACS numbers: 95.36.+x, 97.60.Lf, 98.62.Py, 04.80.Nn, 95.55.Ym, 97.60.Bw, 97.60.Jd

Squeezing of light's quantum noise requires temporal rearranging of photons. This again corresponds to creation of quantum correlations between individual photons. Squeezed light is a nonclassical manifestation of light with great potential in high-precision quantum measurements, for example, in the detection of gravitational waves [C. M. Caves, Phys. Rev. D 23, 1693 (1981)]. Equally promising applications have been proposed in quantum communication [H. P. Yuen and J. H. Shapiro, IEEE Trans. Inf. Theory 24, 657 (1978)]. However, after 20 years of intensive research doubts arose whether strong squeezing can ever be realized as required for eminent applications. Here we show experimentally that strong squeezing of light's quantum noise is possible. We reached a benchmark squeezing factor of 10 in power (10 dB). Thorough analysis reveals that even higher squeezing factors will be feasible in our setup. DOI: 10.1103/PhysRevLett.100.033602 PACS numbers: 42.50.Dv, 03.65.Ta, 04.80.Nn, 42.65.Yj Theoretical considerations about the possible existence of light with squeezed quantum noise can be traced back to the 1920's [1]. However, only after applications for squeezed light were proposed in the 1980's squeezing was discussed in more detail [1][2][3][4][5]. In [2] it was suggested to use squeezed light to improve the sensitivity of kilometre-scale Michelson laser-interferometers for the detection of gravitational waves. Such detectors have now reached a technical standard at which squeezed light can contribute in a valuable way. For example squeezing the quantum noise can provide a sensitivity improvement equivalent to even higher laser powers, however, without increasing the already problematic thermal load inside the interferometer. This is of great relevance for cryogenically cooled detectors. Proof of principle experiments have been successfully conducted [6,7] and squeezed states have been generated also in the audio signal band of ground-based detectors [8,9]. Another field of application is continuousvariable (CV) quantum communication and information [3,10,11]. While discrete-variable quantum information typically relies on single-photon detectors, which are limited in terms of detection speed and quantum efficiency, squeezed light is detected with homodyne and heterodyne detectors which reveal quantum correlations by averaging over a vast number of detected photons. Because of this, high bandwidth and almost perfect detection efficiencies are possible. Squeezed states of light have been used to demonstrate several CV quantum information protocols. They have been used to construct entangled states of light and to demonstrate quantum teleportation [12 -14]. They are a possible resource for secure quantum key distribution protocols [15,16] and for generation of cluster states for universal quantum computing [17]. Recently, squeezed states of light have been used to prepare macroscopic quantum superposition states for quantum information networks [18,19].For all proof of principle experiments so far only modest...