72,652 research outputs found

    An assessment of the newest magnetar-SNR associations

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    Anomalous X-ray Pulsars and Soft-Gamma Repeaters groups are magnetar candidates featuring low characteristic ages (τ=P2P˙\tau = {P\over{2 {\dot P}}}). At least some of them they should still be associated with the remnants of the explosive events in which they were born, giving clues to the type of events leading to their birth and the physics behind the apparent high value of the magnetar magnetic fields. To explain the high values of BB, a self-consistent picture of field growth also suggests that energy injection into the SNR is large and unavoidable, in contrast with the evolution of {\it conventional} SNR. This modified dynamics, in turn, has important implications for the proposed associations. We show that this scenario yields low ages for the new candidates CXOU J171405.7-381031/CTB 37B and XMMU J173203.3-344518/G353.6-0.7, and predicted values agree with recently found P˙{\dot P}, giving support to the overall picture.Comment: Contributed talk to the ASTRONS 2010 Conference, Cesme, Turkey, Aug. 2-6 201

    Intracavity Dye-Laser Absorption Spectroscopy (IDLAS) for application to planetary molecules

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    Time-resolved, quasi-continuous wave, intracavity dye-laser absorption spectroscopy is applied to the investigation of absolute absorption coefficients for vibrational-rotational overtone bands of water at visible wavelengths. Emphasis is placed on critical factors affecting detection sensitivity and data analysis. Typical generation-time dependent absorption spectra are given

    Optical Dipole Trapping beyond Rotating Wave Approximation: The case of Large Detuning

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    We show that the inclusion of counter-rotating terms, usually dropped in evaluations of interaction of an electric dipole of a two level atom with the electromagnetic field, leads to significant modifications of trapping potential in the case of large detuning. The results are shown to be in excellent numerical agreement with recent experimental findings, for the case of modes of Laguerre-Gauss spatial profile.Comment: 13 pages, 2 figure

    Time-dependent Ginzburg-Landau model for light-induced superconductivity in the cuprate LESCO

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    Cavalleri and coworkers have discovered evidence of light-induced superconductivity and related phenomena in several different materials. Here we suggest that some features may be naturally interpreted using a time-dependent Ginzburg-Landau model. In particular, we focus on the lifetime of the transient state in La1.675_{1.675}Eu0.2_{0.2}Sr0.125_{0.125}CuO4_4 (LESCO1/8_{1/8}), which is remarkably long below about 25 K, but exhibits different behavior at higher temperature.Comment: 5 pages, accepted by European Journal of Physics: Special Topic

    Polarisation rotation of slow light with orbital angular momentum in ultracold atomic gases

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    We consider the propagation of slow light with an orbital angular momentum (OAM) in a moving atomic medium. We have derived a general equation of motion and applied it in analysing propagation of slow light with an OAM in a rotating medium, such as a vortex lattice. We have shown that the OAM of slow light manifests itself in a rotation of the polarisation plane of linearly polarised light. To extract a pure rotational phase shift, we suggest to measure a difference in the angle of the polarisation plane rotation by two consecutive light beams with opposite OAM. The differential angle Δα\Delta\alpha_{\ell} is proportional to the rotation frequency of the medium ωrot\omega_{\mathrm{rot}} and the winding number \ell of light, and is inversely proportional to the group velocity of light. For slow light the angle Δα\Delta\alpha_{\ell} should be large enough to be detectable. The effect can be used as a tool for measuring the rotation frequency ωrot\omega_{\mathrm{rot}} of the medium.Comment: 5 pages, 1 figur

    Surface optical vortices

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    It is shown how the total internal reflection of orbital-angular-momentum-endowed light can lead to the generation of evanescent light possessing rotational properties in which the intensity distribution is firmly localized in the vicinity of the surface. The characteristics of these surface optical vortices depend on the form of the incident light and on the dielectric mismatch of the two media. The interference of surface optical vortices is shown to give rise to interesting phenomena, including pattern rotation akin to a surface optical Ferris wheel. Applications are envisaged to be in atom lithography, optical surface tweezers, and spanners

    Chicago Board of Trade Ethanol Contract Efficiency

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    Firms producing ethanol may find management of the price risk associated with production of this leading alternative fuel a key factor to continued success. As with other agricultural commodities, the influence and ability of futures contracts to serve as a risk management tool deserves attention.contract efficiency, ethanol, futures contracts, Crop Production/Industries, Risk and Uncertainty, Q13, Q43, M31,

    Role of three-body interactions in formation of bulk viscosity in liquid argon

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    With the aim of locating the origin of discrepancy between experimental and computer simulation results on bulk viscosity of liquid argon, a molecular dynamic simulation of argon interacting via ab initio pair potential and triple-dipole three-body potential has been undertaken. Bulk viscosity, obtained using Green-Kubo formula, is different from the values obtained from modeling argon using Lennard-Jones potential, the former being closer to the experimental data. The conclusion is made that many-body inter-atomic interaction plays a significant role in formation of bulk viscosity.Comment: 4 pages, 3 figure
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