Optical position meters analyzed in the non-inertial reference frames

In the framework of General Relativity we develop a method for analysis of the operation of the optical position meters in their photodetectors proper reference frames. These frames are non-inertial in general due to the action of external fluctuative forces on meters test masses, including detectors. For comparison we also perform the calculations in the laboratory (globally inertial) reference frame and demonstrate that for certain optical schemes laboratory-based analysis results in unmeasurable quantities, in contrast to the detector-based analysis. We also calculate the response of the simplest optical meters to weak plane gravitational waves and fluctuative motions of their test masses. It is demonstrated that for the round-trip meter analysis in both the transverse-traceless (TT) and local Lorentz (LL) gauges produces equal results, while for the forward-trip meter corresponding results differ in accordance with different physical assumptions (e.g. procedure of clocks synchronization) implicitly underlying the construction of the TT and LL gauges.Comment: 10 pages, 2 figures; co-author added, added section VC with discussion of procedures of clocks synchronization, corrected sign in old Eq.17 (currently it is Eq.18

Anomalous dynamic back-action in interferometers

We analyze the dynamic optomechanical back-action in signal-recycled Michelson and Michelson-Sagnac interferometers that are operated off dark port. We show that in this case --- and in contrast to the well-studied canonical form of dynamic back-action on dark port --- optical damping in a Michelson-Sagnac interferometer acquires a non-zero value on cavity resonance, and additional stability/instability regions on either side of the resonance, revealing new regimes of cooling/heating of micromechanical oscillators. In a free-mass Michelson interferometer for a certain region of parameters we predict a stable single-carrier optical spring (positive spring and positive damping), which can be utilized for the reduction of quantum noise in future-generation gravitational-wave detectors.Comment: 9 pages, 5 figures. Paper reorganize

Observation of generalized optomechanical coupling and cooling on cavity resonance

Optomechanical coupling between a light field and the motion of a cavity mirror via radiation pressure plays an important role for the exploration of macroscopic quantum physics and for the detection of gravitational waves (GWs). It has been used to cool mechanical oscillators into their quantum ground states and has been considered to boost the sensitivity of GW detectors, e.g. via the optical spring effect. Here, we present the experimental characterization of generalized, that is, dispersive and dissipative optomechanical coupling, with a macroscopic (1.5mm)^2-sized silicon nitride (SiN) membrane in a cavity-enhanced Michelson-type interferometer. We report for the first time strong optomechanical cooling based on dissipative coupling, even on cavity resonance, in excellent agreement with theory. Our result will allow for new experimental regimes in macroscopic quantum physics and GW detection

Displacement-noise-free gravitational-wave detection with a single Fabry-Perot cavity: a toy model

We propose a detuned Fabry-Perot cavity, pumped through both the mirrors, as \textit{a toy model} of the gravitational-wave (GW) detector partially free from displacement noise of the test masses. It is demonstrated that the noise of cavity mirrors can be eliminated, but the one of lasers and detectors cannot. The isolation of the GW signal from displacement noise of the mirrors is achieved in a proper linear combination of the cavity output signals. The construction of such a linear combination is possible due to the difference between the reflected and transmitted output signals of detuned cavity. We demonstrate that in low-frequency region the obtained displacement-noise-free response signal is much stronger than the $f^3_{\textrm{gw}}$-limited sensitivity of displacement-noise-free interferometers recently proposed by S. Kawamura and Y. Chen. However, the loss of the resonant gain in the noise cancelation procedure results is the sensitivity limitation of our toy model by displacement noise of lasers and detectors.Comment: 16 pages, 5 figures; extended discussion of basic mechanism of noise cancelation moved to new Sec. II (with new figure), added discussion of laser noise cancelation in Sec. VI D (with new figure

Interaction of plane gravitational waves with a Fabry-Perot cavity in the local Lorentz frame

We analyze the interaction of plane '+'-polarized gravitational waves with a Fabry-Perot cavity in the local Lorentz frame of the cavity input mirror outside of the range of long-wave approximation with the force of radiation pressure taken into account. The obtained detector response signal is represented as a sum of two parts: (i) the phase shift due to displacement of the movable mirror under the influence of gravitational wave and the force of light pressure, and (ii) the phase shift due to direct interaction of gravitational wave with light wave inside the cavity. We obtain formula for the movable mirror law of motion paying close attention to the phenomena of optical rigidity, radiative friction and direct coupling of gravitational wave to light wave. Some issues concerning the detection of high-frequency gravitational waves and the role of optical rigidity in it are discussed. We also examine in detail special cases of optical resonance and small detuning from it and compare our results with the known ones.Comment: 17 pages, 9 figures; corrected references [7,8,34], added 2 new references (currently [35,36]), added comments on (i) relativistic corrections, (ii) detector angular pattern, (iii) quantized electromagnetic field, increased font in figure

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Searching for stochastic gravitational waves using data from the two colocated LIGO Hanford detectors

Searches for a stochastic gravitational-wave background (SGWB) using terrestrial detectors typically involve cross-correlating data from pairs of detectors. The sensitivity of such cross-correlation analyses depends, among other things, on the separation between the two detectors: the smaller the separation, the better the sensitivity. Hence, a colocated detector pair is more sensitive to a gravitational-wave background than a noncolocated detector pair. However, colocated detectors are also expected to suffer from correlated noise from instrumental and environmental effects that could contaminate the measurement of the background. Hence, methods to identify and mitigate the effects of correlated noise are necessary to achieve the potential increase in sensitivity of colocated detectors. Here we report on the first SGWB analysis using the two LIGO Hanford detectors and address the complications arising from correlated environmental noise. We apply correlated noise identification and mitigation techniques to data taken by the two LIGO Hanford detectors, H1 and H2, during LIGO’s fifth science run. At low frequencies, 40–460 Hz, we are unable to sufficiently mitigate the correlated noise to a level where we may confidently measure or bound the stochastic gravitational-wave signal. However, at high frequencies, 460–1000 Hz, these techniques are sufficient to set a 95% confidence level upper limit on the gravitational-wave energy density of Ω(f) < 7.7 × 10[superscript -4](f/900  Hz)[superscript 3], which improves on the previous upper limit by a factor of ~180. In doing so, we demonstrate techniques that will be useful for future searches using advanced detectors, where correlated noise (e.g., from global magnetic fields) may affect even widely separated detectors.National Science Foundation (U.S.)United States. National Aeronautics and Space AdministrationCarnegie TrustDavid & Lucile Packard FoundationAlfred P. Sloan Foundatio

Electrochemical Deposition of Ni–W Crack-Free Coatings

The main features of electrochemical deposition of coatings based on Ni&ndash;W binary alloy in the pulse current mode using pyrophosphate electrolytes were studied. Two electrolytes with a pH of 8.7 and 9.5 were used. The deposition was carried out with the current density varying in the range of 0.01&ndash;0.1 A&middot;cm&minus;2, and the duty cycle (the relative pulse duration) was changed within the range 20&ndash;100%. The surface morphology and elemental and phase composition of the coatings were studied by scanning electron microscopy, energy-dispersive X-ray microanalysis and X-ray diffractometry. The experimental conditions allowing us to achieve the maximum Faradaic efficiency and W content in the coatings were determined. It was found that the pulse current mode enabled the fabrication of crack-free coatings with a thickness greater than 6 &mu;m