3,029 research outputs found

    Multidimensional reconciliation for continuous-variable quantum key distribution

    Get PDF
    We propose a method for extracting an errorless secret key in a continuous-variable quantum key distribution protocol, which is based on Gaussian modulation of coherent states and homodyne detection. The crucial feature is an eight-dimensional reconciliation method, based on the algebraic properties of octonions. Since the protocol does not use any postselection, it can be proven secure against arbitrary collective attacks, by using well-established theorems on the optimality of Gaussian attacks. By using this new coding scheme with an appropriate signal to noise ratio, the distance for secure continuous-variable quantum key distribution can be significantly extended.Comment: 8 pages, 3 figure

    Serving Others at the Expense of Self: The Relationship Between Nonprofit CEO Compensation and Performance in Trade and Professional Associations

    Get PDF
    This paper investigates the organizational importance of relative CEO compensation in trade associations and professional societies. It is known that there is variation in how much pay is tied to performance in different subcategories of nonprofit organizations. However, instead of looking at how performance affects pay, we investigate how CEO compensation affects organization performance when CEOs are aware of their peer compensation and are able to influence their own. We hypothesized that CEOs who knowingly earn less will be associated with both greater financial and nonfinancial organizational performance. This altruistic perspective draws on theories from leadership and psychology rather than the more typical agency perspective and focuses on the alignment between CEO and stakeholders in a nonprofit setting. We find strong support for the relationship between lower relative CEO compensation and organization performance, while results for the moderating effect of organizational size are mixed

    Noisy Preprocessing and the Distillation of Private States

    Get PDF
    We provide a simple security proof for prepare & measure quantum key distribution protocols employing noisy processing and one-way postprocessing of the key. This is achieved by showing that the security of such a protocol is equivalent to that of an associated key distribution protocol in which, instead of the usual maximally-entangled states, a more general {\em private state} is distilled. Besides a more general target state, the usual entanglement distillation tools are employed (in particular, Calderbank-Shor-Steane (CSS)-like codes), with the crucial difference that noisy processing allows some phase errors to be left uncorrected without compromising the privacy of the key.Comment: 4 pages, to appear in Physical Review Letters. Extensively rewritten, with a more detailed discussion of coherent --> iid reductio

    Detecting a stochastic background of gravitational radiation: Signal processing strategies and sensitivities

    Get PDF
    We analyze the signal processing required for the optimal detection of a stochastic background of gravitational radiation using laser interferometric detectors. Starting with basic assumptions about the statistical properties of a stochastic gravity-wave background, we derive expressions for the optimal filter function and signal-to-noise ratio for the cross-correlation of the outputs of two gravity-wave detectors. Sensitivity levels required for detection are then calculated. Issues related to: (i) calculating the signal-to-noise ratio for arbitrarily large stochastic backgrounds, (ii) performing the data analysis in the presence of nonstationary detector noise, (iii) combining data from multiple detector pairs to increase the sensitivity of a stochastic background search, (iv) correlating the outputs of 4 or more detectors, and (v) allowing for the possibility of correlated noise in the outputs of two detectors are discussed. We briefly describe a computer simulation which mimics the generation and detection of a simulated stochastic gravity-wave signal in the presence of simulated detector noise. Numerous graphs and tables of numerical data for the five major interferometers (LIGO-WA, LIGO-LA, VIRGO, GEO-600, and TAMA-300) are also given. The treatment given in this paper should be accessible to both theorists involved in data analysis and experimentalists involved in detector design and data acquisition.Comment: 81 pages, 30 postscript figures, REVTE
    • …
    corecore