11,969 research outputs found

    Quantum interference and entanglement induced by multiple scattering of light

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    We report on the effects of quantum interference induced by transmission of an arbitrary number of optical quantum states through a multiple scattering medium. We identify the role of quantum interference on the photon correlations and the degree of continuous variable entanglement between two output modes. It is shown that the effect of quantum interference survives averaging over all ensembles of disorder and manifests itself as increased photon correlations giving rise to photon anti-bunching. Finally, the existence of continuous variable entanglement correlations in a volume speckle pattern is predicted. Our results suggest that multiple scattering provides a promising way of coherently interfering many independent quantum states of light of potential use in quantum information processing.Comment: 5 pages including 4 figure

    Nodal-to-nodeless superconducting order parameter in LaFeAs1x_{1-x}Px_xO synthesized under high pressure

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    Similar to chemical doping, pressure produces and stabilizes new phases of known materials, whose properties may differ greatly from those of their standard counterparts. Here, by considering a series of LaFeAs1x_{1-x}Px_xO iron-pnictides synthesized under high-pressure high-temperature conditions, we investigate the simultaneous effects of pressure and isoelectronic doping in the 1111 family. Results of numerous macro- and microscopic technique measurements, unambiguously show a radically different phase diagram for the pressure-grown materials, characterized by the lack of magnetic order and the persistence of superconductivity across the whole 0.3x0.70.3 \leq x \leq 0.7 doping range. This unexpected scenario is accompanied by a branching in the electronic properties across x=0.5x = 0.5, involving both the normal and superconducting phases. Most notably, the superconducting order parameter evolves from nodal (for x<0.5x < 0.5) to nodeless (for x0.5x \geq 0.5), in clear contrast to other 1111 and 122 iron-based materials grown under ambient-pressure conditions.Comment: 9 pages, 7 figures, Suppl. materia

    Intermittency in Two-Dimensional Turbulence with Drag

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    We consider the enstrophy cascade in forced two-dimensional turbulence with a linear drag force. In the presence of linear drag, the energy wavenumber spectrum drops with a power law faster than in the case without drag, and the vorticity field becomes intermittent, as shown by the anomalous scaling of the vorticity structure functions. Using a previous theory, we compare numerical simulation results with predictions for the power law exponent of the energy wavenumber spectrum and the scaling exponents of the vorticity structure functions ζ2q\zeta_{2q} obtained in terms of the distribution of finite time Lyapunov exponents. We also study, both by numerical experiment and theoretical analysis, the multifractal structure of the viscous enstrophy dissipation in terms of its R\'{e}nyi dimension spectrum DqD_q and singularity spectrum f(α)f(\alpha). We derive a relation between DqD_q and ζ2q\zeta_{2q}, and discuss its relevance to a version of the refined similarity hypothesis. In addition, we obtain and compare theoretically and numerically derived results for the dependence on separation rr of the probability distribution of \delta_{\V{r}}\omega, the difference between the vorticity at two points separated by a distance rr. Our numerical simulations are done on a 4096×40964096 \times 4096 grid.Comment: 18 pages, 17 figure

    Twelve Channel Optical Fiber Connector Assembly: From Commercial Off the Shelf to Space Flight Use

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    The commercial off the shelf (COTS) twelve channel optical fiber MTP array connector and ribbon cable assembly is being validated for space flight use and the results of this study to date are presented here. The interconnection system implemented for the Parallel Fiber Optic Data Bus (PFODB) physical layer will include a 100/140 micron diameter optical fiber in the cable configuration among other enhancements. As part of this investigation, the COTS 62.5/125 microns optical fiber cable assembly has been characterized for space environment performance as a baseline for improving the performance of the 100/140 micron diameter ribbon cable for the Parallel FODB application. Presented here are the testing and results of random vibration and thermal environmental characterization of this commercial off the shelf (COTS) MTP twelve channel ribbon cable assembly. This paper is the first in a series of papers which will characterize and document the performance of Parallel FODB's physical layer from COTS to space flight worthy

    Virginia Domestic Relations Handbook and Virginia Domestic Relations Case Finder

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    The Michie Company has released two publications dealing with the changing area of domestic relations law and which provide the busy Virginia practitioner with easy access to the areas within the field of family law practice and the relevant case authorities

    A Systematic Survey of the Effects of Wind Mass Loss Algorithms on the Evolution of Single Massive Stars

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    Mass loss is a key uncertainty in the evolution of massive stars. Stellar evolution calculations must employ parametric algorithms for mass loss, and usually only include stellar winds. We carry out a parameter study of the effects of wind mass loss on massive star evolution using the open-source stellar evolution code MESA. We provide a systematic comparison of wind mass loss algorithms for solar-metallicity, nonrotating, single stars in the initial mass range of 1535M15-35\,M_\odot. We consider combinations drawn from two hot phase algorithms, three cool phase algorithms, and two Wolf-Rayet algorithms. We consider linear wind efficiency scale factors of 11, 0.330.33, and 0.10.1 to account for reductions in mass loss rates due to wind inhomogeneities. We find that the initial to final mass mapping for each zero-age main-sequence (ZAMS) mass has a 50%\sim 50\% uncertainty if all algorithm combinations and wind efficiencies are considered. The ad-hoc efficiency scale factor dominates this uncertainty. While the final total mass and internal structure of our models vary tremendously with mass loss treatment, final observable parameters are much less sensitive for ZAMS mass 30M\lesssim 30\,M_\odot. This indicates that uncertainty in wind mass loss does not negatively affect estimates of the ZAMS mass of most single-star supernova progenitors from pre-explosion observations. Furthermore, we show that the internal structure of presupernova stars is sensitive to variations in both main sequence and post main-sequence mass loss. We find that the compactness parameter ξM/R(M)\xi\propto M/R(M) varies by as much as 30%30\% for a given ZAMS mass evolved with different wind efficiencies and mass loss algorithm combinations. [abridged]Comment: Accepted for publication on A&A, 22 pages + 2 appendixes, 12 figures, online input parameters available at https://stellarcollapse.org/renzo2017 and data at https://zenodo.org/record/292924#.WK0q2tWi6W

    Polarized neutron channeling as a tool for the investigations of weakly magnetic thin films

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    We present and apply a new method to measure directly weak magnetization in thin films. The polarization of a neutron beam channeling through a thin film structure is measured after exiting the structure edge as a microbeam. We have applied the method to a tri-layer thin film structure acting as a planar waveguide for polarized neutrons. The middle guiding layer is a rare earth based ferrimagnetic material TbCo5 with a low magnetization of about 20 mT. We demonstrate that the channeling method is more sensitive than the specular neutron reflection method
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