8,647 research outputs found

    Té dulce y cigarrillos: el sabor de la vida de refugiado en Jordania

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    Las restricciones sobre la movilidad, la prohibición de trabajar y el sentimiento de marginación provocan un aburrimiento absoluto que supone sin duda un motivo de sufrimiento entre los refugiados de Jordania

    Quantum phase-space analysis of the pendular cavity

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    We perform a quantum mechanical analysis of the pendular cavity, using the positive-P representation, showing that the quantum state of the moving mirror, a macroscopic object, has noticeable effects on the dynamics. This system has previously been proposed as a candidate for the quantum-limited measurement of small displacements of the mirror due to radiation pressure, for the production of states with entanglement between the mirror and the field, and even for superposition states of the mirror. However, when we treat the oscillating mirror quantum mechanically, we find that it always oscillates, has no stationary steady-state, and exhibits uncertainties in position and momentum which are typically larger than the mean values. This means that previous linearised fluctuation analyses which have been used to predict these highly quantum states are of limited use. We find that the achievable accuracy in measurement is far worse than the standard quantum limit due to thermal noise, which, for typical experimental parameters, is overwhelming even at 2 mK.Comment: 25 pages, 6 figures To be published in Phys. Rev.

    Fractional topological phase on spatially encoded photonic qudits

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    We discuss the appearance of fractional topological phases on cyclic evolutions of entangled qudits encoded on photonic degrees of freedom. We show how the spatial correlations between photons generated by spontaneous parametric down conversion can be used to evidence the multiple topological phases acquired by entangled qudits and the role played by the Hilbert space dimension. A realistic experimental proposal is presented with numerical predictions of the expected results.Comment: 7 pages, 5 figure captions, 9 figure

    Fraser of cryptophthalmosis syndrome: A case report

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    Fraser or cryptophthalmos syndrome is a rare autosomal recessive disorder characterized by major features such as cryptophthalmos, syndactyly, and abnormal genitalia. Consanguinity is reported in 15-24.8% of the cases. The diagnosis of this syndrome can be made on clinical examination; therefore we present the clinical findings of a rare case of Fraser syndrome in a female infant

    Refugees’ contentious politics and the case of Syrian activists in Jordan

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    This paper was presented at a workshop on ‘The Long-term Challenges of Forced Migration: Local and Regional Perspectives from Lebanon, Jordan and Iraq’ organised by the LSE Middle East Centre in June 2016. It was published as part of a collected papers volume available in English and Arabic

    Spin-orbit mode transfer via a classical analog of quantum teleportation

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    We translate the quantum teleportation protocol into a sequence of coherent operations involving three degrees of freedom of a classical laser beam. The protocol, which we demonstrate experimentally, transfers the polarisation state of the input beam to the transverse mode of the output beam. The role of quantum entanglement is played by a non-separable mode describing the path and transverse degrees of freedom. Our protocol illustrates the possibility of new optical applications based on this intriguing classical analogue of quantum entanglement.Comment: 5 pages, 7 figure

    Nonlinear Interferometry via Fock State Projection

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    We use a photon-number resolving detector to monitor the photon number distribution of the output of an interferometer, as a function of phase delay. As inputs we use coherent states with mean photon number up to seven. The postselection of a specific Fock (photon-number) state effectively induces high-order optical non-linearities. Following a scheme by Bentley and Boyd [S.J. Bentley and R.W. Boyd, Optics Express 12, 5735 (2004)] we explore this effect to demonstrate interference patterns a factor of five smaller than the Rayleigh limit.Comment: 4 pages, 5 figure

    Conservation of Orbital Angular Momentum in Stimulated Down-Conversion

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    We report on an experiment demonstrating the conservation of orbital angular momentum in stimulated down-conversion. The orbital angular momentum is not transferred to the individual beams of the spontaneous down-conversion, but it is conserved when twin photons are taken individually. We observe the conservation law for an individual beam of the down-conversion through cavity-free stimulated emission.Comment: Submitted for publication in Phys. Rev. Let
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