Adaptive Optical Phase Estimation Using Time-Symmetric Quantum Smoothing

Quantum parameter estimation has many applications, from gravitational wave detection to quantum key distribution. We present the first experimental demonstration of the time-symmetric technique of quantum smoothing. We consider both adaptive and non-adaptive quantum smoothing, and show that both are better than their well-known time-asymmetric counterparts (quantum filtering). For the problem of estimating a stochastically varying phase shift on a coherent beam, our theory predicts that adaptive quantum smoothing (the best scheme) gives an estimate with a mean-square error up to $2\sqrt{2}$ times smaller than that from non-adaptive quantum filtering (the standard quantum limit). The experimentally measured improvement is $2.24 \pm 0.14$

Ca-substitution and O-doping effects in superconducting Cu(Ba0.8Sr0.2)2(Yb1-xCax)Cu2O6+z obtained from neutron diffraction refinements

Distinct calcium and oxygen doping effects were studied in the Cu(Ba0.8Sr0.2)2(Yb1−xCax)Cu2O6+z (Cu−1212:P) system by means of neutron diffraction and superconducting quantum interference device experiments in the wide substitution ranges of 0<~x<~0.35 and 0<z<1. The effectiveness of the two different ways to introduce holes into the CuO2 planes was compared both in respect to the capability to increase Tc and in terms of the hole production as estimated from neutron-diffraction data via bond-valence-sum calculation. Oxygen doping was found to increase the hole concentration less efficiently, and further, at a certain hole concentration value higher Tc values were obtained with calcium substitution than with oxygen doping. The two different hole-doping methods exhibited also different Tc vs Cu-O bond length relations. As a conclusion, the possible roles of the hole distribution in the in-plane Cu-O bond and the flatness of the CuO2 planes in determining the superconducting properties were recognized.Peer reviewe

RCSB PDB Mobile: iOS and Android mobile apps to provide data access and visualization to the RCSB Protein Data Bank.

SummaryThe Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB) resource provides tools for query, analysis and visualization of the 3D structures in the PDB archive. As the mobile Web is starting to surpass desktop and laptop usage, scientists and educators are beginning to integrate mobile devices into their research and teaching. In response, we have developed the RCSB PDB Mobile app for the iOS and Android mobile platforms to enable fast and convenient access to RCSB PDB data and services. Using the app, users from the general public to expert researchers can quickly search and visualize biomolecules, and add personal annotations via the RCSB PDB's integrated MyPDB service.Availability and implementationRCSB PDB Mobile is freely available from the Apple App Store and Google Play (http://www.rcsb.org)

Impurity scattering in unconventional density waves

We have investigated the effect of nonmagnetic impurities on the quasi-one-dimensional unconventional density wave (UDW) ground state. The thermodynamics were found to be close to those of a d-wave superconductor in the Born limit. Four different optical conductivity curves were found depending on the direction of the applied electric field and on the wavevector dependence of the gap.Comment: 14 pages, 9 figure

Ground-based millimeter-wave observation of stratospheric ClO over Atacama, Chile in the mid-latitude Southern Hemisphere

We have performed ground-based measurements of stratospheric chlorine monoxide (ClO) during the summer in 2009 over the Atacama highland, Chile, a new observing site in the mid-latitude region in the Southern Hemisphere, by using a millimeter-wave spectroscopic radiometer. The radiometer, equipped with a superconducting receiver and a digital Fourier spectrometer, was developed by Nagoya University, and the new observing system provides us high sensitivity and stable performance to measure the very weak ClO lines. The receiver noise temperature of the superconducting receiver is 170 K in DSB. To reveal the diurnal variation of ClO, we retrieved the vertical mixing ratio profiles by the weighted-damped least-squares algorithm applied for the spectral data at 203 GHz obtained between 5 and 16 December 2009. The total error on the retrieval is estimated to be 20% to 30% in an altitude range from 40 km to 50 km. The amplitude of the diurnal variation is estimated as 33% of the daytime average at 40 km. The observed time variation shows a pattern similar to that of the previous works observed in the northern mid-latitude region