45,315 research outputs found

    Qubit Channels Can Require More Than Two Inputs to Achieve Capacity

    Get PDF
    We give examples of qubit channels that require three input states in order to achieve the Holevo capacity.Comment: RevTex, 5 page, 4 figures

    Evidence for a planetary mass third body orbiting the binary star KIC 5095269

    Get PDF
    In this paper, we report the evidence for a planetary mass body orbiting the close binary star KIC 5095269. This detection arose from a search for eclipse timing variations among the more than 2,000 eclipsing binaries observed by Kepler. Light curve and periodic eclipse time variations have been analysed using Systemic and a custom Binary Eclipse Timings code based on the Transit Analysis Package which indicates a 7.70±0.08MJup7.70\pm0.08M_{Jup} object orbiting every 237.7±0.1d237.7\pm0.1d around a 1.2M⊙1.2M_\odot primary and 0.51M⊙0.51M_\odot secondary in an 18.6d orbit. A dynamical integration over 10710^7 years suggests a stable orbital configuration. Radial velocity observations are recommended to confirm the properties of the binary star components and the planetary mass of the companion.Comment: 8 pages, 7 figures, Accepted for publication in MNRA

    Maximization of capacity and p-norms for some product channels

    Full text link
    It is conjectured that the Holevo capacity of a product channel \Omega \otimes \Phi is achieved when product states are used as input. Amosov, Holevo and Werner have also conjectured that the maximal p-norm of a product channel is achieved with product input states. In this paper we establish both of these conjectures in the case that \Omega is arbitrary and \Phi is a CQ or QC channel (as defined by Holevo). We also establish the Amosov, Holevo and Werner conjecture when \Omega is arbitrary and either \Phi is a qubit channel and p=2, or \Phi is a unital qubit channel and p is integer. Our proofs involve a new conjecture for the norm of an output state of the half-noisy channel I \otimes \Phi, when \Phi is a qubit channel. We show that this conjecture in some cases also implies additivity of the Holevo capacity

    Large U_{e3} and Tri-bimaximal Mixing

    Full text link
    We investigate in a model-independent way to what extent one can perturb tri-bimaximal mixing in order to generate a sizable value of |U_{e3}|, while at the same time keeping solar neutrino mixing near its measured value, which is close to sin^2 theta_{12} = 1/3. Three straightforward breaking mechanisms to generate |U_{e3}| of about 0.1 are considered. For charged lepton corrections, the suppression of a sizable contribution to sin^2 theta_{12} can be achieved if CP violation in neutrino oscillations is almost maximal. Generation of the indicated value of |U_{e3}| of about 0.1 through renormalization group corrections requires the neutrinos to be quasi-degenerate in mass. The consistency with the allowed range of sin^2 theta_{12} together with large running of |U_{e3}| forces one of the Majorana phases to be close to pi. This implies large cancellations in the effective Majorana mass governing neutrino-less double beta, constraining it to lie near its minimum allowed value of m_0 cos 2 theta_{12}, where m_0 is greater than about 0.1 eV. Finally, explicit breaking of the neutrino mass matrix in the inverted hierarchical and quasi-degenerate neutrino mass spectrum cases is similarly correlated with the effective Majorana mass, although to a lesser extent. The implied values for the atmospheric neutrino mixing angle theta_{23} are given in all cases.Comment: 20 pages, 9 figure

    Model for the unidirectional motion of a dynein molecule

    Full text link
    Cytoplasmic dyneins transport cellular organelles by moving on a microtubule filament. It has been found recently that depending on the applied force and the concentration of the adenosine triphosphate (ATP) molecules, dynein's step size varies. Based on these studies, we propose a simple model for dynein's unidirectional motion taking into account the variations in its step size. We study how the average velocity and the relative dispersion in the displacement vary with the applied load. The model is amenable to further extensions by inclusion of details associated with the structure and the processivity of the molecule.Comment: 10 pages, 5 figure

    Aerodynamic size distribution of suspended particulate matter in the ambient air in the city of Cleveland, Ohio

    Get PDF
    The City of Cleveland Division of Air Pollution Control and NASA jointly investigated the chemical and physical characteristics of the suspended particulate matter in Cleveland, and as part of the program, measurements of the particle size distribution of ambient air samples at five urban locations during August and September 1972 were made using high-volume cascade impactions. The distributions were evaluated for lognormality, and the mass median diameters were compared between locations and as a function of resultant wind direction. Junge-type distributions were consistent with dirty continental aerosols. About two-thirds of the suspended particulate matter observed in Cleveland is less than 7 microns in diameter

    Development of a mechatronic sorting system for removing contaminants from wool

    Get PDF
    Automated visual inspection (AVI) systems have been extended to many fields, such as agriculture and the food, plastic and textile industries. Generally, most visual systems only inspect product defects, and then analyze and grade them due to the lack of any sorting function. This main reason rests with the difficulty of using the image data in real time. However, it is increasingly important to either sort good products from bad or grade products into separate groups usingAVI systems. This article describes the development of a mechatronic sorting system and its integration with a vision system for automatically removing contaminants from wool in real time. The integration is implemented by a personal computer, which continuously processes live images under the Windows 2000 operating system. The developed real-time sorting approach is also applicable to many other AVI systems
    • …
    corecore