22,155 research outputs found

    Spinless Two-Band Model in Infinite Dimensions

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    A spinless two-band model is studied in infinite dimension limit. Starting from the atomic limit, the formal exact solution of the model is obtained by means a perturbative treatment of the hopping and hybridisation terms. The model is solved in closed form in high dimensions assuming no local spin fluctuations. The non-Fermi liquid properties appearing in the metallic phase are analysed through the behaviour of the density of states and the self-energy near the Fermi level.Comment: 4 pages, 3 figures, to appear in PRB-Breif Repor

    General one-loop formulas for decay hZγh\rightarrow Z\gamma

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    Radiative corrections to the hZγh\rightarrow Z\gamma are evaluated in the one-loop approximation. The unitary gauge gauge is used. The analytic result is expressed in terms of the Passarino-Veltman functions. The calculations are applicable for the Standard Model as well for a wide class of its gauge extensions. In particular, the decay width of a charged Higgs boson H±W±γH^\pm \rightarrow W^\pm\gamma can be derived. The consistence of our formulas and several specific earlier results is shown.Comment: 33 pages, 3 figures, a new section (V) and references were improved in the published versio

    On Universality in Human Correspondence Activity

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    Identifying and modeling patterns of human activity has important ramifications in applications ranging from predicting disease spread to optimizing resource allocation. Because of its relevance and availability, written correspondence provides a powerful proxy for studying human activity. One school of thought is that human correspondence is driven by responses to received correspondence, a view that requires distinct response mechanism to explain e-mail and letter correspondence observations. Here, we demonstrate that, like e-mail correspondence, the letter correspondence patterns of 16 writers, performers, politicians, and scientists are well-described by the circadian cycle, task repetition and changing communication needs. We confirm the universality of these mechanisms by properly rescaling letter and e-mail correspondence statistics to reveal their underlying similarity.Comment: 17 pages, 3 figures, 1 tabl

    Non-Fermi Liquids in the Extended Hubbard Model

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    I summarize recent work on non-Fermi liquids within certain generalized Anderson impurity model as well as in the large dimensionality (DD) limit of the two-band extended Hubbard model. The competition between local charge and spin fluctuations leads either to a Fermi liquid with renormalized quasiparticle excitations, or to non-Fermi liquids with spin-charge separation. These results provide new insights into the phenomenological similarities and differences between different correlated metals. While presenting these results, I outline a general strategy of local approach to non-Fermi liquids in correlated electron systems.Comment: 30 pages, REVTEX, 14 figures included. To appear in ``Non Fermi Liquid Physics'', J. Phys: Cond. Matt. (1997

    Multicultural Competencies of Healthcare Professionals and Disability-Inclusive in Telehealth during the COVID-19 Pandemic

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    There is evidence that people with disabilities are more likely to be discriminated against and to have disproportionate health care disparities compared to people who are able-bodied during the devastating COVID-19 pandemic. In light of COVID-19, telehealth has been transformed to the primary health care delivery due to social restrictions of most, globally. Disability-inclusive telehealth design can promote culturally diverse groups access and more accurate COVID-19 information, knowledge, public health measures, and guidelines of preventive strategies for acquiring COVID-19. Applying multicultural competencies is required for healthcare providers to maximize health engagement and outcomes of PWD. In many areas of health care, healthcare professionals recognize needs, expectations, and perceptions of diverse disability populations. That being said, healthcare professionals should implement appropriate interactions with a patient with a disability and provide culturally responsive telehealth services for other underrepresented groups as well. Hence, the multicultural competencies of healthcare professionals and disability responsive telehealth systems can assist PWD to mitigate health care disparities

    Hall Effect in Nested Antiferromagnets Near the Quantum Critical Point

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    We investigate the behavior of the Hall coefficient in the case of antiferromagnetism driven by Fermi surface nesting, and find that the Hall coefficient should abruptly increase with the onset of magnetism, as recently observed in vanadium doped chromium. This effect is due to the sudden removal of flat portions of the Fermi surface upon magnetic ordering. Within this picture, the Hall coefficient should scale as the square of the residual resistivity divided by the impurity concentration, which is consistent with available data.Comment: published version; an accidental interchange in the quoting of sigmaxyzsigma_{xyz} analytic dependencies was correcte

    Extended calculations of energy levels, radiative properties, AJA_{J}, BJB_{J} hyperfine interaction constants, and Land\'e gJg_{J}-factors for nitrogen-like \mbox{Ge XXVI}

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    Employing two state-of-the-art methods, multiconfiguration Dirac--Hartree--Fock and second-order many-body perturbation theory, highly accurate calculations are performed for the lowest 272 fine-structure levels arising from the 2s22p32s^{2} 2p^{3}, 2s2p42s 2p^{4}, 2p52p^{5}, 2s22p23l2s^{2} 2p^{2} 3l~(l=s,p,dl=s,p,d), 2s2p33l2s 2p^{3}3l (l=s,p,dl=s,p,d), and 2p43l2p^{4} 3l (l=s,p,dl=s,p,d) configurations in nitrogen-like Ge XXVI. Complete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Land\'e gJg_{J}-factors, and E1, E2, M1, M2 line strengths, oscillator strengths, and transition rates among these 272 levels are provided. Comparisons are made between the present two data sets, as well as with other available experimental and theoretical values. The present data are accurate enough for identification and deblending of emission lines involving the n=3n=3 levels, and are also useful for modeling and diagnosing fusion plasmas

    Dynamics of long-range order in an exciton-polariton condensate

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    We report on time resolved measurements of the first order spatial coherence in an exciton polariton Bose-Einstein condensate. Long range spatial coherence is found to set in right at the onset of stimulated scattering, on a picosecond time scale. The coherence reaches its maximum value after the population and decays slower, staying up to a few hundreds of picoseconds. This behavior can be qualitatively reproduced, using a stochastic classical field model describing interaction between the polariton condensate and the exciton reservoir within a disordered potential.Comment: 7 pages, 4 figure

    Estimation of conditional laws given an extreme component

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    Let (X,Y)(X,Y) be a bivariate random vector. The estimation of a probability of the form P(YyX>t)P(Y\leq y \mid X >t) is challenging when tt is large, and a fruitful approach consists in studying, if it exists, the limiting conditional distribution of the random vector (X,Y)(X,Y), suitably normalized, given that XX is large. There already exists a wide literature on bivariate models for which this limiting distribution exists. In this paper, a statistical analysis of this problem is done. Estimators of the limiting distribution (which is assumed to exist) and the normalizing functions are provided, as well as an estimator of the conditional quantile function when the conditioning event is extreme. Consistency of the estimators is proved and a functional central limit theorem for the estimator of the limiting distribution is obtained. The small sample behavior of the estimator of the conditional quantile function is illustrated through simulations.Comment: 32 pages, 5 figur

    Bayesian Networks for Max-linear Models

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    We study Bayesian networks based on max-linear structural equations as introduced in Gissibl and Kl\"uppelberg [16] and provide a summary of their independence properties. In particular we emphasize that distributions for such networks are generally not faithful to the independence model determined by their associated directed acyclic graph. In addition, we consider some of the basic issues of estimation and discuss generalized maximum likelihood estimation of the coefficients, using the concept of a generalized likelihood ratio for non-dominated families as introduced by Kiefer and Wolfowitz [21]. Finally we argue that the structure of a minimal network asymptotically can be identified completely from observational data.Comment: 18 page
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