Vibrational Spectroscopic Investigation of Molecular Crystals of Methylmercury(II) Halides

A nearly full assignment of the vibrational modes of methylmercury halide crystals has been proposed. Factor group analysis has been used to derive the vibrational selection rules for the lattice modes. It is concluded that the D2hU structure with four molecules in the unit cell. Lattice modes for CH.-sHgl and CD.-jHgl can be assigned on the basis of C2hU substructure with two molecules per unit cell. The bromide gave an ultra-low wavenumber band (7.0 cm-1) which we were unable to assign. Force constants have been calculated on the basis of a primitive unit cell (containig two molecules). The internal HgX stretching force constants 2.112, 1.658, 1.507 and 1.347 N cm-1 and the transverse translatory force constants 0.719, 0.364, 0.266 and 0.218 N cm-1 obtained for fluoride, chloride, bromide, and iodide, respectively, show strong dependence on the kind of halide

Violation of the Leggett-Garg inequality with weak measurements of photons

By weakly measuring the polarization of a photon between two strong polarization measurements, we experimentally investigate the correlation between the appearance of anomalous values in quantum weak measurements, and the violation of realism and non-intrusiveness of measurements. A quantitative formulation of the latter concept is expressed in terms of a Leggett-Garg inequality for the outcomes of subsequent measurements of an individual quantum system. We experimentally violate the Leggett-Garg inequality for several measurement strengths. Furthermore, we experimentally demonstrate that there is a one-to-one correlation between achieving strange weak values and violating the Leggett-Garg inequality.Comment: 5 pages, 4 figure

Facebook's Mobile Career

At the end of its first decade, Facebook’s identity, popularity, and characteristics are shaped in important ways by its becoming a form of mobile media, as much as it as platform associated with Internet and social media. This paper seeks to explore and understand Facebook as the important force in mobile media and communication it now is. It draws upon and combines perspectives from technology production, design, and economy, as well as user adoption, consumption, practices, affect, emotion, and resistance. The paper discusses the beginnings of mobile Facebook, and the early adoption of mobile Facebook associated with the rise of smartphones. The second part of the paper explores Facebook’s integration with photography (with Instagram) and social games (such as Zynga’s Farmville). The paper argues that Facebook’s mobile career is an accomplishment that has distinctively melded evolving affordances, everyday use across a wide range of settings, as well as political economies, corporate strategy, and design.Australian Research Counci

Weak measurement of photon polarization by back-action induced path interference

The essential feature of weak measurements on quantum systems is the reduction of measurement back-action to negligible levels. To observe the non-classical features of weak measurements, it is therefore more important to avoid additional back-action errors than it is to avoid errors in the actual measurement outcome. In this paper, it is shown how an optical weak measurement of diagonal (PM) polarization can be realized by path interference between the horizontal (H) and vertical (V) polarization components of the input beam. The measurement strength can then be controlled by rotating the H and V polarizations towards each other. This well-controlled operation effectively generates the back-action without additional decoherence, while the visibility of the interference between the two beams only limits the measurement resolution. As the experimental results confirm, we can obtain extremely high weak values, even at rather low visibilities. Our method therefore provides a realization of weak measurements that is extremely robust against experimental imperfections.Comment: 11 pages, 3 figure

A burst search for gravitational waves from binary black holes

Compact binary coalescence (CBC) is one of the most promising sources of gravitational waves. These sources are usually searched for with matched filters which require accurate calculation of the GW waveforms and generation of large template banks. We present a complementary search technique based on algorithms used in un-modeled searches. Initially designed for detection of un-modeled bursts, which can span a very large set of waveform morphologies, the search algorithm presented here is constrained for targeted detection of the smaller subset of CBC signals. The constraint is based on the assumption of elliptical polarisation for signals received at the detector. We expect that the algorithm is sensitive to CBC signals in a wide range of masses, mass ratios, and spin parameters. In preparation for the analysis of data from the fifth LIGO-Virgo science run (S5), we performed preliminary studies of the algorithm on test data. We present the sensitivity of the search to different types of simulated CBC waveforms. Also, we discuss how to extend the results of the test run into a search over all of the current LIGO-Virgo data set.Comment: 12 pages, 4 figures, 2 tables, submitted for publication in CQG in the special issue for the conference proceedings of GWDAW13; corrected some typos, addressed some minor reviewer comments one section restructured and references updated and correcte

Challenging Perceptions of Disability through Performance Poetry Methods: The "Seen but Seldom Heard" Project.

This paper considers performance poetry as a method to explore lived experiences of disability. We discuss how poetic inquiry used within a participatory arts-based research framework can enable young people to collectively question society’s attitudes and actions towards disability. Poetry will be considered as a means to develop a more accessible and effective arena in which young people with direct experience of disability can be empowered to develop new skills that enable them to tell their own stories. Discussion of how this can challenge audiences to critically reflect upon their own perceptions of disability will also be developed

Upper Limits on a Stochastic Background of Gravitational Waves

The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of Ω_0<8.4×10^(-4) in the 69–156 Hz band is ~10^5 times lower than the previous result in this frequency range

Phenomenological template family for black-hole coalescence waveforms

Recent progress in numerical relativity has enabled us to model the non-perturbative merger phase of the binary black-hole coalescence problem. Based on these results, we propose a phenomenological family of waveforms which can model the inspiral, merger, and ring-down stages of black hole coalescence. We also construct a template bank using this family of waveforms and discuss its implementation in the search for signatures of gravitational waves produced by black-hole coalescences in the data of ground-based interferometers. This template bank might enable us to extend the present inspiral searches to higher-mass binary black-hole systems, i.e., systems with total mass greater than about 80 solar masses, thereby increasing the reach of the current generation of ground-based detectors.Comment: Minor changes, Submitted to Class. Quantum Grav. (Proc. GWDAW11

Status of NINJA: the Numerical INJection Analysis project

The 2008 NRDA conference introduced the Numerical INJection Analysis project (NINJA), a new collaborative effort between the numerical relativity community and the data analysis community. NINJA focuses on modeling and searching for gravitational wave signatures from the coalescence of binary system of compact objects. We review the scope of this collaboration and the components of the first NINJA project, where numerical relativity groups shared waveforms and data analysis teams applied various techniques to detect them when embedded in colored Gaussian noise