No abstract available

[en] Aims: to evaluate myocardial perfusion defects (MPD) prevalence and left ventricular function in CAF patients from a distinct referral basis (a GH and CH populations). Materials and Methods: a retrospective cross-sectional survey including 171 CAF (43 from GH and 128 from CH) and 5415 control patients (2222 from GH and 3193 from CH) submitted to rest/stress myocardial perfusion gated SPECT with Tc99m-MIBI. The following items were collected from CAF patients: the percentage of patients with MPD, the type (fixed, reversible or mixed) and number of segments with MPD and left ventricular ejection fraction (LVEF). The control patients percentage of MPD, their type and number were also collected. Results: CAF from GH and CH were not significantly different in the number of patients with MPD, mean number of segments affected, and LVEF. In GH patients, the CAF group had more segments with MPD (2,4x1,6 p<0,01) and lower LVEF (37%x52% p<0,01) than control group. CAF patients from CH also showed lower LVEF (40%x58% p<0,01) and more fixed MPD (40%x18% p<0,01) than their control group population. Conclusion: our data showed similar prevalence of MPD and reduced LVEF values between CAF patients from a GH and referral CH. The CAF group from CH seemed to have more fixed MPD perhaps reflecting more severe coronary artery disease population or referral bias. The data appears to support the evaluation of myocardial ischemia as a part of CAF possible etiologies. Caution is advised in LVEF evaluation of CAF patients due to increased variability of R-R interval

[en] The speed meter concept has been identified as a technique that can potentially provide laser-interferometric measurements at a sensitivity level which surpasses the standard quantum limit (SQL) over a broad frequency range. As with other sub-SQL measurement techniques, losses play a central role in speed meter interferometers and they ultimately determine the quantum noise limited sensitivity that can be achieved. So far in the literature, the quantum noise limited sensitivity has only been derived for lossless or lossy cases using certain approximations (for instance that the arm cavity round trip loss is small compared to the arm cavity mirror transmission). In this article we present a generalized, analytical treatment of losses in speed meters that allows accurate calculation of the quantum noise limited sensitivity of Sagnac speed meters with arm cavities. In addition, our analysis allows us to take into account potential imperfections in the interferometer such as an asymmetric beam splitter or differences of the reflectivities of the two arm cavity input mirrors. Finally, we use the examples of the proof-of-concept Sagnac speed meter currently under construction in Glasgow and a potential implementation of a Sagnac speed meter in the Einstein Telescope to illustrate how our findings affect Sagnac speed meters with metre- and kilometre-long baselines. (paper)

[en] Speedmeters are known to be quantum non-demolition devices and, by potentially providing sensitivity beyond the standard quantum limit, become interesting for third generation gravitational wave detectors. Here we introduce a new configuration, the sloshing-Sagnac interferometer, and compare it to the more established ring-Sagnac interferometer. The sloshing-Sagnac interferometer is designed to provide improved quantum noise limited sensitivity and lower coating thermal noise than standard position meter interferometers employed in current gravitational wave detectors. We compare the quantum noise limited sensitivity of the ring-Sagnac and the sloshing-Sagnac interferometers, in the frequency range, from 5 Hz to 100 Hz, where they provide the greatest potential benefit. We evaluate the improvement in terms of the unweighted noise reduction below the standard quantum limit, and by finding the range up to which binary black hole inspirals may be observed. The sloshing-Sagnac was found to give approximately similar or better sensitivity than the ring-Sagnac in all cases. We also show that by eliminating the requirement for maximally-reflecting cavity end mirrors with correspondingly-thick multi-layer coatings, coating noise can be reduced by a factor of approximately 2.2 compared to conventional interferometers. (paper)

[en] Optical rigidity will play an important role in improving the sensitivity of future generations of gravitational wave (GW) interferometers, which employ high laser power in order to reach and exceed the standard quantum limit. Several experiments have demonstrated the combined effect of two optical springs on a single system for very low-weight mirror masses or membranes. In this paper we investigate the complex interactions between multiple optical springs and the surrounding apparatus in a system of comparable dynamics to a large-scale GW detector. Using three 100 g mirrors to form a coupled cavity system capable of sustaining two or more optical springs, we demonstrate a number of different regimes of opto-mechanical rigidity and measurement techniques. Our measurements reveal couplings between each optical spring and the control loops that can affect both the achievable increase in sensitivity and the stability of the system. Hence this work establishes a better understanding of the realisation of these techniques and paves the way to their application in future GW observatories, such as upgrades to Advanced LIGO. (paper)

[en] The AEI 10 m prototype will be an ultra-low displacement noise facility consisting of an L-shaped ultra-high vacuum system with about 10 m long arms, excellent seismic isolation, a well-stabilized high power laser and other advanced interferometry techniques. In the first round of experiments an interferometer to measure at the standard quantum limit of classical interferometry will be set up. This paper describes the status of the AEI 10 m prototype and its individual sub-systems as of April 2012. (paper)

[en] Waveguide mirrors (WGMs) possess nano-structured surfaces which can potentially provide a significant reduction in thermal noise over conventional dielectric mirrors. To avoid introducing additional phase noise from the motion of the mirror transverse to the reflected light, however, they must possess a mechanism to suppress the phase effects associated with the incident light translating across the nano-structured surface. It has been shown that with carefully chosen parameters this additional phase noise can be suppressed. We present an experimental measurement of the coupling of transverse to longitudinal displacements in such a WGM designed for 1064 nm light. We place an upper limit on the level of measured transverse to longitudinal coupling of one part in seventeen thousand with 95% confidence, representing a significant improvement over a previously measured grating mirror. (paper)

[en] The Sagnac speed metre topology has been identified as a promising technique to reduce quantum back-action in gravitational-wave interferometers. However, imbalance of the main beamsplitter has been shown to increase the coupling of laser noise to the detection port, thus reducing the quantum noise superiority of the speed metre, compared to conventional approaches, in particular at low frequencies. In this paper, we show that by implementing a balanced homodyne readout scheme with a suitable choice of the point from which the local oscillator (LO) is derived, the excess laser noise contribution is partly compensated, and the resulting speed metre can be more sensitive than state-of-the-art position metres. This is achieved by picking-off the LO from either the reflection port of the interferometer or the anti-reflective coating surface of the main beamsplitter. We show that either approach relaxes the relative intensity noise (RIN) requirement of the input laser. For example, for a beam splitter imbalance of 0.1% in the Glasgow speed metre proof of concept experiment, the RIN requirement at frequency of 100 Hz decreases from $4\times <!--\; ??\; -->{10}^{-<!--\; ???\; -->10}/\sqrt{\mathrm{H}\mathrm{z}}$ to $4\times <!--\; ??\; -->{10}^{-<!--\; ???\; -->7}/\sqrt{\mathrm{H}\mathrm{z}}$, moving the RIN requirement from a value that is hard to achieve in practice, to one which is routinely obtained. (paper)

[en] Currently, the AEI 10 m Prototype is being set up at the Albert Einstein Institute in Hannover, Germany. The Suspension Platform Interferometer (SPI) will be an additional interferometer set up inside the vacuum envelope of the AEI 10 m Prototype. It will interferometrically link the three suspended in-vacuum tables. The inter-table distance will be 11.65 m. The SPI will measure and stabilise the relative motions between these tables for all degrees of freedom, except roll around the optical axis. In this way, all tables can be regarded as one large platform. The design goal is 100 pm/√Hz differential distance stability between 10mHz and 100Hz.

[en] A 10 m prototype interferometer facility is currently being set up at the AEI in Hannover, Germany. The prototype interferometer will be housed inside a 100 m³ ultra-high vacuum envelope. Seismically isolated optical tables inside the vacuum system will be interferometrically interconnected via a suspension platform interferometer. Advanced isolation techniques will be used, such as inverted pendulums and geometrical anti-spring filters in combination with multiple-cascaded pendulum suspensions, containing an all-silica monolithic last stage. The light source is a 35 W Nd:YAG laser, geometrically filtered by passing it through a photonic crystal fibre and a rigid pre-modecleaner cavity. Laser frequency stabilisation will be achieved with the aid of a high finesse suspended reference cavity in conjunction with a molecular iodine reference. Coating thermal noise will be reduced by the use of Khalili cavities as compound end mirrors. Data acquisition and control of the experiments is based on the AdvLIGO digital control and data system. The aim of the project is to test advanced techniques for GEO 600 as well as to conduct experiments in macroscopic quantum mechanics. Reaching standard quantum-limit sensitivity for an interferometer with 100 g mirrors and subsequently breaching this limit, features most prominently among these experiments. In this paper we present the layout and current status of the AEI 10 m Prototype Interferometer project.