1,060 research outputs found

    Information hiding and retrieval in Rydberg wave packets using half-cycle pulses

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    We demonstrate an information hiding and retrieval scheme with the relative phases between states in a Rydberg wave packet acting as the bits of a data register. We use a terahertz half-cycle pulse (HCP) to transfer phase-encoded information from an optically accessible angular momentum manifold to another manifold which is not directly accessed by our laser pulses, effectively hiding the information from our optical interferometric measurement techniques. A subsequent HCP acting on these wave packets reintroduces the information back into the optically accessible data register manifold which can then be `read' out.Comment: 4 pages, 4 figure

    A typical reconstruction limit of compressed sensing based on Lp-norm minimization

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    We consider the problem of reconstructing an NN-dimensional continuous vector \bx from PP constraints which are generated by its linear transformation under the assumption that the number of non-zero elements of \bx is typically limited to ρN\rho N (0ρ10\le \rho \le 1). Problems of this type can be solved by minimizing a cost function with respect to the LpL_p-norm ||\bx||_p=\lim_{\epsilon \to +0}\sum_{i=1}^N |x_i|^{p+\epsilon}, subject to the constraints under an appropriate condition. For several pp, we assess a typical case limit αc(ρ)\alpha_c(\rho), which represents a critical relation between α=P/N\alpha=P/N and ρ\rho for successfully reconstructing the original vector by minimization for typical situations in the limit N,PN,P \to \infty with keeping α\alpha finite, utilizing the replica method. For p=1p=1, αc(ρ)\alpha_c(\rho) is considerably smaller than its worst case counterpart, which has been rigorously derived by existing literature of information theory.Comment: 12 pages, 2 figure

    Quantum phase retrieval of a Rydberg wave packet using a half-cycle pulse

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    A terahertz half-cycle pulse was used to retrieve information stored as quantum phase in an NN-state Rydberg atom data register. The register was prepared as a wave packet with one state phase-reversed from the others (the "marked bit"). A half-cycle pulse then drove a significant portion of the electron probability into the flipped state via multimode interference.Comment: accepted by PR

    Optimally shaped terahertz pulses for phase retrieval in a Rydberg atom data register

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    We employ Optimal Control Theory to discover an efficient information retrieval algorithm that can be performed on a Rydberg atom data register using a shaped terahertz pulse. The register is a Rydberg wave packet with one consituent orbital phase-reversed from the others (the ``marked bit''). The terahertz pulse that performs the decoding algorithm does so by by driving electron probability density into the marked orbital. Its shape is calculated by modifying the target of an optimal control problem so that it represents the direct product of all correct solutions to the algorithm.Comment: 6 pages, 3 figure

    Absolute Neutron Flux from a Raα+Be Source

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    Multiscale Computations on Neural Networks: From the Individual Neuron Interactions to the Macroscopic-Level Analysis

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    We show how the Equation-Free approach for multi-scale computations can be exploited to systematically study the dynamics of neural interactions on a random regular connected graph under a pairwise representation perspective. Using an individual-based microscopic simulator as a black box coarse-grained timestepper and with the aid of simulated annealing we compute the coarse-grained equilibrium bifurcation diagram and analyze the stability of the stationary states sidestepping the necessity of obtaining explicit closures at the macroscopic level. We also exploit the scheme to perform a rare-events analysis by estimating an effective Fokker-Planck describing the evolving probability density function of the corresponding coarse-grained observables

    Introduction: reconsidering the region in India: mobilities, actors and development politics

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    In this introduction to a special issue on ‘Reconsidering the Region in India’, we aim to develop a synthetic and theoretically nuanced account of the multifarious ways in which the idea of region has been imbricated in diverse spatial, political, cultural and socio-economic configurations. We draw from various bodies of anthropological, geographic and historical literature to elaborate on three themes that we believe are central to understanding contemporary processes of region-making in India: trans-regional mobilities and connections; the actors who produce and perform regional imaginaries; and changing regional politics of development.IS

    Impact Of Death-Related Television Programming On Advertising Evaluation

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    Programming that depicts or implies death constitutes a vital component of daily television broadcasts, yet the impact of such programming on the evaluation of embedded advertising remains unexplored. Using terror management theory, we propose that exposure to routine and commonplace death-related television programming will lead to the differential evaluation of ensuing advertisements depending on whether they are perceived to be of domestic or foreign origin, and that this effect is contingent on the nature of the death-related cognitions at play at the time of ad exposure. Further, the death-related program context effects on embedded advertising are unique—ads at the end, not the beginning, of the embedded pod are affected by programming content. Based on the empirical findings from four studies we identify the cognitive processes underlying consumers’ ad evaluation, isolate the pod positions when context effects are observed, and suggest a framework for television commercial scheduling

    BREXIT Election:Forecasting a Conservative Party Victory through the Pound using ARIMA and Facebook\u27s Prophet

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    On the 30th October, 2019, the markets watched as British Prime Minister, Boris Johnson, took a massive political gamble to call a general election to break the Withdrawal Agreement stalemate in the House of Commons to “Get BREXIT Done”. The pound had been politically sensitive owing to BREXIT uncertainty. With the polls indicating a Conservative win on 4thDecember, 2019, the margin of victory could be observed through increases in the pound. The outcome of a Conservative party victory would benefit the pound by removing the current market turbulence. We look to provide a short-term forecast of the pound. Our approach focuses on modelling the GBP/EUR and GBP/USD Fx from the inception of BREXIT referendum talks from the 1stJanuary, 2016 to the conclusion of the BREXIT election on the 12thDecember, 2019, focusing on forecasted increases in the pound from the 4thDecember, 2019. We construct two machine learning models in the form of an Auto Regressive Integrated Moving Average (ARIMA) financial time series and an additive regression financial time series using Facebook’s Prophet to investigate the hypothesis that the polls prediction of a Conservative victory could be validated by forecasted increases in the pound. The efficiency of the forecasted models was then tested based on MAPE and MSE criteria. Our results found that the ARIMA and Prophet models were effective and proficient in forecasting the polls prediction on the 4thDecember, 2019 of a Conservative win by validation of forecasted increases in the pound. The ARIMA (4,1,0) model resulted in forecasts with the lowest MAPE and MAE

    Youth futures and a masculine development ethos in the regional story of Uttarakhand

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    Research on the Uttarakhand region, which became a new state in 2000, has focused largely on agrarian livelihoods, religious rituals, development demands, ecological politics and the role of women in regional social movements. This essay discusses another dimension of the regional imaginary—that of a masculine development ethos. Based on ethnographic research and print media sources, this essay focuses on stories, politics, mobilities and imaginations of young men in the years immediately after the achievement of statehood. Despite increased outmigration of youth in search of employment, many young men expressed the dream of maintaining livelihoods in the familiar towns and rural spaces of Uttarakhand, describing their home region as a source of power and agency. In rallies and in print media, young (mostly upper caste) men expressed their disillusionment with the government and the promises of statehood, arguing that their aspirations for development and employment were left unfulfilled. Gendered stories of the region, told in Hindi in rallies and print media, contained references to local places, people and historical events and were produced through local connections and know-how, fostering a regional youth politics. The article argues that Uttarakhand as a region is shaped by the politics of local actors as well as embodied forms of aspiration, affiliation and mobility.IS
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