633 research outputs found

    The best of two worlds: between-method triangulation in feminist economic research.

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    Assumptions applied in Orthodox Economic methods are criticised for being an inadequate depiction of reality. This is particularly the case from the perspective of Feminist Economics. Gender biases are reflected in the quantitative data sources and methods commonly applied for economic research. These include male biases in statistical data, a focus on outcomes rather than processes as well as the neglect of reproductive work and its interaction with market work. To overcome these problems, this paper introduces between-method triangulation, i.e. the combination of quantitative and qualitative methods of data generation and analysis, as an innovative and more realistic methodology to conduct gendered economic analysis. It draws on the authors’ recent empirical work on the Indonesian and Mauritian labour markets where between-method triangulation was employed. The approach is shown to be able to enhance empirical economic analysis by mutually validating results. Furthermore, the approach is shown to remove gender biases in economic analysis by analysing conflicting evidence and by complementing quantitative with qualitative findings in light of feminist economics theory

    Metastable Innershell Molecular State (MIMS)

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    We propose that the existence of Metastable Innershell Molecular State (MIMS) was experimentally discovered by Bae et al. in hypervelocity (v>100km/s) impact of nanoparticles. The decay of MIMS resulted in the observed intense soft x-rays in the range of 75 - 100 eV in agreement with Winterberg's recent prediction.Comment: Submitted to Physics Letters

    Relaxation oscillations, stability, and cavity feedback in a superradiant Raman laser

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    We experimentally study the relaxation oscillations and amplitude stability properties of an optical laser operating deep into the bad-cavity regime using a laser-cooled 87^{87}Rb Raman laser. By combining measurements of the laser light field with nondemolition measurements of the atomic populations, we infer the response of the gain medium represented by a collective atomic Bloch vector. The results are qualitatively explained with a simple model. Measurements and theory are extended to include the effect of intermediate repumping states on the closed-loop stability of the oscillator and the role of cavity feedback on stabilizing or enhancing relaxation oscillations. This experimental study of the stability of an optical laser operating deep into the bad-cavity regime will guide future development of superradiant lasers with ultranarrow linewidths.Comment: 9 pages, 6 figure

    Diffractive Optics for Gravitational Wave Detectors

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    All-reflective interferometry based on nano-structured diffraction gratings offers new possibilities for gravitational wave detection. We investigate an all-reflective Fabry-Perot interferometer concept in 2nd order Littrow mount. The input-output relations for such a resonator are derived treating the grating coupler by means of a scattering matrix formalism. A low loss dielectric reflection grating has been designed and manufactured to test the properties of such a grating cavity

    Image transmission through a stable paraxial cavity

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    We study the transmission of a monochromatic "image" through a paraxial cavity. Using the formalism of self-transform functions, we show that a transverse degenerate cavity transmits the self-transform part of the image, with respect to the field transformation over one round-trip of the cavity. This formalism gives a new insight on the understanding of the behavior of a transverse degenerate cavity, complementary to the transverse mode picture. An experiment of image transmission through a hemiconfocal cavity show the interest of this approach.Comment: submitted to Phys. Rev.

    Rotationally induced vortices in optical cavity modes

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    We show that vortices appear in the modes of an astigmatic optical cavity when it is put into rotation about its optical axis. We study the properties of these vortices and discuss numerical results for a specific realization of such a set-up. Our method is exact up to first order in the time-dependent paraxial approximation and involves bosonic ladder operators in the spirit of the quantum-mechanical harmonic oscillator.Comment: 8 pages, 5 figures. Accepted for publication in a special issue (singular optics 2008) of Journal of Optics A: Pure and Applied Optic

    On the statistics of resonances and non-orthogonal eigenfunctions in a model for single-channel chaotic scattering

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    We describe analytical and numerical results on the statistical properties of complex eigenvalues and the corresponding non-orthogonal eigenvectors for non-Hermitian random matrices modeling one-channel quantum-chaotic scattering in systems with broken time-reversal invariance.Comment: 4 pages, 2 figure

    Gauge Theory for the Rate Equations: Electrodynamics on a Network

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    Systems of coupled rate equations are ubiquitous in many areas of science, for example in the description of electronic transport through quantum dots and molecules. They can be understood as a continuity equation expressing the conservation of probability. It is shown that this conservation law can be implemented by constructing a gauge theory akin to classical electrodynamics on the network of possible states described by the rate equations. The properties of this gauge theory are analyzed. It turns out that the network is maximally connected with respect to the electromagnetic fields even if the allowed transitions form a sparse network. It is found that the numbers of degrees of freedom of the electric and magnetic fields are equal. The results shed light on the structure of classical abelian gauge theory beyond the particular motivation in terms of rate equations.Comment: 4 pages, 2 figures included, v2: minor revision, as publishe

    Optical vernier technique for in-situ measurement of the length of long Fabry-Perot cavities

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    We propose a method for in-situ measurement of the length of kilometer size Fabry-Perot cavities in laser gravitational wave detectors. The method is based on the vernier, which occurs naturally when the laser incident on the cavity has a sideband. By changing the length of the cavity over several wavelengths we obtain a set of carrier resonances alternating with sideband resonances. From the measurement of the separation between the carrier and a sideband resonance we determine the length of the cavity. We apply the technique to the measurement of the length of a Fabry-Perot cavity in the Caltech 40m Interferometer and discuss the accuracy of the technique.Comment: LaTeX 2e, 12 pages, 4 figure

    Optical measurement of torque exerted on an elongated object by a non-circular laser beam

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    We have developed a scheme to measure the optical torque, exerted by a laser beam on a phase object, by measuring the orbital angular momentum of the transmitted beam. The experiment is a macroscopic simulation of a situation in optical tweezers, as orbital angular momentum has been widely used to apply torque to microscopic objects. A hologram designed to generate LG02 modes and a CCD camera are used to detect the orbital component of the beam. Experimental results agree with theoretical numerical calculations, and the strength of the orbital component suggest its usefulness in optical tweezers for micromanipulation.Comment: 6 pages, 7 figures, v2: minor typographical correction
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