3,176 research outputs found

    Collective T- and P- Odd Electromagnetic Moments in Nuclei with Octupole Deformations

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    Parity and time invariance violating forces produce collective P- and T- odd moments in nuclei with static octupole deformation. Collective Schiff moment, electric octupole and dipole and also magnetic quadrupole appear due to the mixing of rotational levels of opposite parity and can exceed single-particle moments by more than a factor of 100. This enhancement is due to two factors, the collective nature of the intrinsic moments and the small energy separation between members of parity doublets. The above moments induce T- and P- odd effects in atoms and molecules. Experiments with such systems may improve substantially the limits on time reversal violation.Comment: 9 pages, Revte

    A construction of bent functions from plateaued functions

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    In this presentation, a technique for constructing bent functions from plateaued functions is introduced and analysed. This generalizes earlier techniques for constructing bent from near-bent functions. Using this construction, we obtain a big variety of inequivalent bent functions, some weakly regular and some non-weakly regular. Classes of bent function with some additional properties that enable the construction of strongly regular graphs are constructed, and explicit expressions for bent functions with maximal degree are presented

    Wisdom across the ages and its modern day relevance

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    Nearby Doorways, Parity Doublets and Parity Mixing in Compound Nuclear States

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    We discuss the implications of a doorway state model for parity mixing in compound nuclear states. We argue that in order to explain the tendency of parity violating asymmetries measured in 233^{233}Th to have a common sign, doorways that contribute to parity mixing must be found in the same energy neighbourhood of the measured resonance. The mechanism of parity mixing in this case of nearby doorways is closely related to the intermediate structure observed in nuclear reactions in which compound states are excited. We note that in the region of interest (233^{233}Th) nuclei exhibit octupole deformations which leads to the existence of nearby parity doublets. These parity doublets are then used as doorways in a model for parity mixing. The contribution of such mechanism is estimated in a simple model.Comment: 11 pages, REVTE

    Emergent Chiral Symmetry: Parity and Time Reversal Doubles

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    There are numerous examples of approximately degenerate states of opposite parity in molecular physics. Theory indicates that these doubles can occur in molecules that are reflection-asymmetric. Such parity doubles occur in nuclear physics as well, among nuclei with odd A \sim 219-229. We have also suggested elsewhere that such doubles occur in particle physics for baryons made up of `cbu' and `cbd' quarks. In this article, we discuss the theoretical foundations of these doubles in detail, demonstrating their emergence as a surprisingly subtle consequence of the Born-Oppenheimer approximation, and emphasizing their bundle-theoretic and topological underpinnings. Starting with certain ``low energy'' effective theories in which classical symmetries like parity and time reversal are anomalously broken on quantization, we show how these symmetries can be restored by judicious inclusion of ``high-energy'' degrees of freedom. This mechanism of restoring the symmetry naturally leads to the aforementioned doublet structure. A novel by-product of this mechanism is the emergence of an approximate symmetry (corresponding to the approximate degeneracy of the doubles) at low energies which is not evident in the full Hamiltonian. We also discuss the implications of this mechanism for Skyrmion physics, monopoles, anomalies and quantum gravity.Comment: 32 pages, latex. minor changes in presentation and reference

    Parametrization of the octupole degrees of freedom

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    A simple parametrization for the octupole collective variables is proposed and the symmetries of the wave functions are discussed in terms of the solutions corresponding to the vibrational limit. [PACS: 21.60Ev, 21.60.Fw, 21.10.Re]Comment: 14 page

    Parity Doubles in Quark Physics

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    There are numerous examples of very nearly degenerate states of opposite parity in molecular physics. The ammonia maser is based on one such double. Theory shows that these parity doubles can occur if the nuclear shape in the molecule is reflection-asymmetric because the time scales of the shape and the electronic cloud are well-separated. Parity doubles occur in nuclear physics as well for odd A219229A \sim 219-229. We discuss the theoretical foundation of these doubles and on that basis suggest that parity doubles should occur in particle physics too. In particular they should occur among baryons composed of cbucbu and cbdcbd quarks.Comment: minor changes made; to appear in Phys.Rev.Let

    Progress on catastrophic health spending in 133 countries: a retrospective observational study

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    Background The goal of universal health coverage (UHC) requires inter alia that families who get needed health care do not suffer undue financial hardship as a result. This can be measured by the percentage of people in households whose out-of-pocket health expenditures are large relative to their income or consumption. We aimed to estimate the global incidence of catastrophic health spending, trends between 2000 and 2010, and associations between catastrophic health spending and macroeconomic and health system variables at the country level. Methods We did a retrospective observational study of health spending using data obtained from household surveys. Of 1566 potentially suitable household surveys, 553 passed quality checks, covering 133 countries between 1984 and 2015. We defined health spending as catastrophic when it exceeded 10% or 25% of household consumption. We estimated global incidence by aggregating up from every country, using a survey for the year in question when available, and interpolation and model-based estimates otherwise. We used multiple regression to explore the relation between a country’s incidence of catastrophic spending and gross domestic product (GDP) per person, the Gini coefficient for income inequality, and the share of total health expenditure spent by social security funds, other government agencies, private insurance schemes, and non-profit institutions. Findings The global incidence of catastrophic spending at the 10% threshold was estimated as 9·7% in 2000, 11·4% in 2005, and 11·7% in 2010. Globally, 808 million people in 2010 incurred catastrophic health spending. Across 94 countries with two or more survey datapoints, the population-weighted median annual rate of change of catastrophic payment incidence was positive whatever catastrophic payment incidence measure was used. Incidence of catastrophic payments was correlated positively with GDP per person and the share of GDP spent on health, and incidence correlated negatively with the share of total health spending channelled through social security funds and other government agencies. Interpretation The proportion of the population that is supposed to be covered by health insurance schemes or by national or subnational health services is a poor indicator of financial protection. Increasing the share of GDP spent on health is not sufficient to reduce catastrophic payment incidence; rather, what is required is increasing the share of total health expenditure that is prepaid, particularly through taxes and mandatory contributions

    Progress on catastrophic health spending in 133 countries: a retrospective observational study

    Get PDF
    Background The goal of universal health coverage (UHC) requires inter alia that families who get needed health care do not suffer undue financial hardship as a result. This can be measured by the percentage of people in households whose out-of-pocket health expenditures are large relative to their income or consumption. We aimed to estimate the global incidence of catastrophic health spending, trends between 2000 and 2010, and associations between catastrophic health spending and macroeconomic and health system variables at the country level. Methods We did a retrospective observational study of health spending using data obtained from household surveys. Of 1566 potentially suitable household surveys, 553 passed quality checks, covering 133 countries between 1984 and 2015. We defined health spending as catastrophic when it exceeded 10% or 25% of household consumption. We estimated global incidence by aggregating up from every country, using a survey for the year in question when available, and interpolation and model-based estimates otherwise. We used multiple regression to explore the relation between a country’s incidence of catastrophic spending and gross domestic product (GDP) per person, the Gini coefficient for income inequality, and the share of total health expenditure spent by social security funds, other government agencies, private insurance schemes, and non-profit institutions. Findings The global incidence of catastrophic spending at the 10% threshold was estimated as 9·7% in 2000, 11·4% in 2005, and 11·7% in 2010. Globally, 808 million people in 2010 incurred catastrophic health spending. Across 94 countries with two or more survey datapoints, the population-weighted median annual rate of change of catastrophic payment incidence was positive whatever catastrophic payment incidence measure was used. Incidence of catastrophic payments was correlated positively with GDP per person and the share of GDP spent on health, and incidence correlated negatively with the share of total health spending channelled through social security funds and other government agencies. Interpretation The proportion of the population that is supposed to be covered by health insurance schemes or by national or subnational health services is a poor indicator of financial protection. Increasing the share of GDP spent on health is not sufficient to reduce catastrophic payment incidence; rather, what is required is increasing the share of total health expenditure that is prepaid, particularly through taxes and mandatory contributions

    Photometric Monitoring of Open Clusters I. The Survey

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    Open clusters, which have age, abundance, and extinction information from studies of main-sequence turn off stars, are the ideal location in which to determine the mass-luminosity-radius relation for low-mass stars. We have undertaken a photometric monitoring survey of open clusters in the Galaxy designed to detect low-mass eclipsing binary systems through variations in their relative light curves. Our aim is to provide an improved calibration of the mass-luminosity-radius relation for low-mass stars and brown dwarfs, to test stellar structure and evolution models, and to help quantify the contribution of low-mass stars to the global mass census in the Galaxy. In this paper we present our survey, describing the data and outlining the analysis techniques. We study six nearby open clusters, with a range of ages from 0.2\sim 0.2 to 4 Gyr and metallicities from approximately solar to -0.2dex. We monitor a field-of-view of > 1 square degree per target cluster, well beyond the characteristic cluster radius, over timescales of hours, days, and months with a sampling rate optimised for the detection of eclipsing binaries with periods of hours to days. Our survey depth is designed to detect eclipse events in a binary with a primary star of \lesssim 0.3~M_{\sun}. Our data have a photometric precision of 3\sim 3 mmag at I16I\approx 16.Comment: 50 pages, 18 figures, accepted for publication in A
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