다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

J. Appl. Cryst.の発刊に際して

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

/pdf/the-observation-of-gravitational-waves-from-a-binary-black-58srpupgg9.pdf

The Observation of Gravitational Waves from a Binary Black Hole Merger

We review the field of cavity optomechanics, which explores the interaction between electromagnetic radiation and nano- or micromechanical motion This review covers the basics of optical cavities and mechanical resonators, their mutual optomechanical interaction mediated by the radiation pressure force, the large variety of experimental systems which exhibit this interaction, optical measurements of mechanical motion, dynamical backaction amplification and cooling, nonlinear dynamics, multimode optomechanics, and proposals for future cavity quantum optomechanics experiments In addition, we describe the perspectives for fundamental quantum physics and for possible applications of optomechanical devices

Cavity Optomechanics

Bose-Einstein condensation (BEC) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system, and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum-statistical. The study of BEC in weakly interacting systems which can be controlled and observed with precision holds the promise of revealing new macroscopic quantum phenomena that can be understood from first principles.

Bose-Einstein condensation in a gas of sodium atoms

http://exphy.uni-duesseldorf.de/optical_clock/PDF/Satellite%20Optical%20Clocks%20Berlin%2007-2006.pdf

Satellite Optical Clocks: Fundamental Tests and Applications

A worldwide effort is underway to achieve optical oscillators with instabilities < 1 Hz. These activities are mostly geared toward frequency standards based on lasers stabilized to transitions in cold atoms or trapped ions. There is a need to develop complementary laser frequency stabilization schemes, for highresolution spectroscopy experiments, as flywheel oscillators for atom/ion frequency standards, and for dock-dock comparison experiments aimed at fundamental tests.

http://exphy.uni-duesseldorf.de/Publikationen/1997/prl78_4741.pdf

Cryogenic Optical Resonators: A New Tool For Laser Frequency Stabilization Below The 10-14 Level

NEXCERA is a machinable and highly polishable ceramic with attractive properties for use in precision instruments, in particular because its coefficient of thermal expansion exhibits a zero crossing at room temperature. We performed an accurate measurement of the long-term drift of the length of a 12~cm long NEXCERA block by using it as a spacer of a high-finesse optical cavity. At room temperature, we found a fractional length drift rate $L^{-1}d\Delta L/dt=-1.74\times10^{-8}~\mathrm{yr}^{-1}$.

Characterization of the long-term dimensional stability of a NEXCERA block using the optical resonator technique

Ultracold molecular hydrogen (D/sub 2//sup +/) is produced by sympathetic cooling in a linear Paul trap. With this method the translational degrees of freedom of the molecules are cooled by Coulomb interaction with laser-cooled /sup 9/Be/sup +/. This work shows that sympathetic cooling and crystallization is possible down to mass ratios of 0.45. Using molecular dynamics simulations, the mass range for sympathetic cooliing is predicted. By employin a light and a heavy species of laser-cooled ions (/sup 9/Be/sup +/ and e.g. /sup 137/Ba/sup +/) the mass range from 2 to 20 000 amu, i.e. from the simplest molecule to complex proteins, can be sympathetically cooled.

https://ieeexplore.ieee.org/iel5/9181/29129/01314167.pdf

Ultra-cold molecules in Coulomb crystals

We analyze the properties of optical cavities contained in spacers with approximate octahedral symmetry and made of different materials, following the design of Webster and Gill (Opt Lett 36:3572, 2011). We show that, for isotropic materials with Young’s modulus less than 200 GPa, the Poisson’s ratio $$\nu$$
 must lie in a “magic” range $$0.13<\nu <0.23$$
 to null the influence of the forces supporting the spacer. This restriction can be overcome with the use of anisotropic materials such as silicon. A detailed study aiming at identification of all suitable crystal orientations of silicon with respect to the resonator body is performed, and the relation to the Poisson’s ratio and the Young’s modulus along these orientations is discussed. We also perform an analysis of the sensitivity of the cavity performance to errors in spacer manufacturing. We find that the orientation of the [110] or [100] crystallographic directions oriented along one of the three optical axes of the resonator provides low sensitivities to imprecise manufacturing and interesting options for fundamental physics experiments.

Stephan Schiller

Papers

Satellite Optical Clocks: Fundamental Tests and Applications

Cryogenic Optical Resonators: A New Tool For Laser Frequency Stabilization Below The 10-14 Level

Characterization of the long-term dimensional stability of a NEXCERA block using the optical resonator technique

Ultra-cold molecules in Coulomb crystals

Simulation of force-insensitive optical cavities in cubic spacers