84 research outputs found

    A natural orbital method for the electron momentum distribution in matter

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    A variational method for many electron system is applied to momentum distribution calculations. The method uses a generating two-electron geminal and the amplitudes of the occupancies of one particle natural orbitals as variational parameters. It introduces correlation effects beyond the free fermion nodal structure.Comment: 3 pages, Latex, revised paper with new reference

    Entanglement as Measure of Electron-Electron Correlation in Quantum Chemistry Calculations

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    In quantum chemistry calculations, the correlation energy is defined as the difference between the Hartree-Fock limit energy and the exact solution of the nonrelativistic Schrodinger equation. With this definition, the electron correlation effects are not directly observable. In this report, we show that the entanglement can be used as an alternative measure of the electron correlation in quantum chemistry calculations. Entanglement is directly observable and it is one of the most striking properties of quantum mechanics. As an example we calculate the entanglement for He atom and H2 molecule with different basis sets.Comment: 12 pages, 2 figure

    Majorana: from atomic and molecular, to nuclear physics

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    In the centennial of Ettore Majorana's birth (1906-1938?), we re-examine some aspects of his fundamental scientific production in atomic and molecular physics, including a not well known short communication. There, Majorana critically discusses Fermi's solution of the celebrated Thomas-Fermi equation for electron screening in atoms and positive ions. We argue that some of Majorana's seminal contributions in molecular physics already prelude to the idea of exchange interactions (or Heisenberg-Majorana forces) in his later workson theoretical nuclear physics. In all his papers, he tended to emphasize the symmetries at the basis of a physical problem, as well as the limitations, rather than the advantages, of the approximations of the method employed.Comment: to appear in Found. Phy

    When Institutional Work Backfires: Organizational Control Of Professional Work In The Pharmaceutical Industry

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    Integrating institutional and role theories, this paper develops a Logics–Roles– Action (LRA) framework for understanding how for-profit organizations structure institutional work to managerially control the work of professionals they employ. Structurally, this institutional work involves three elements: (1) internalizing pluralistic logics (logics); (2) institutionalizing distinct roles embedded in these logics (roles); and (3) scripting goal-oriented role enactment plans (action). An empirical examination of the LRA framework in the pharmaceutical industry evidences four distinct organizational strategies that script role enactments of sales professionals in their interactions with physicians. Each strategy is intended to reaffirm prevailing institutional logics, but eventually backfires by disrupting the very institutional structures that it seeks to maintain and replicate. We show that this disruptive effect is mediated by changes in the social knowledge of institutional work. We close with theoretical and managerial implications for organizational structuring of institutional work and dynamics of institutional change

    Study of DJ meson decays to D+π−, D0π+ and D∗+π− final states in pp collisions

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    A study of D+π−, D0π+ and D∗+π− final states is performed using pp collision data, corresponding to an integrated luminosity of 1.0 fb−1, collected at a centre-of-mass energy of 7 TeV with the LHCb detector. The D1(2420)0 resonance is observed in the D∗+π− final state and the D∗2(2460) resonance is observed in the D+π−, D0π+ and D∗+π− final states. For both resonances, their properties and spin-parity assignments are obtained. In addition, two natural parity and two unnatural parity resonances are observed in the mass region between 2500 and 2800 MeV. Further structures in the region around 3000 MeV are observed in all the D∗+π−, D+π− and D0π+ final states

    La tassonomia XBRL italiana della nota integrativa: analisi delle fonti normative

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    Through a wide-ranging critical review of relevant publications, we explore and articulate what constitutes the sensemaking perspective in organization studies, as well as its range of applications and limitations. More specifically, we argue that sensemaking in organizations has been seen as consisting of specific episodes, is triggered by ambiguous events, occurs through specific processes, generates specific outcomes, and is influenced by several situational factors. Furthermore, we clarify the application range of the sensemaking perspective and identify, as well as account for, the types and aspects of organizational sensemaking that have been under-researched. We critically discuss the criticism that the sensemaking perspective has received so far and selectively expand on it. Finally, we identify the main limitations of the sensemaking perspective, which, if tackled, will advance it: the neglect of prospective sensemaking, the exclusive focus on disruptive episodes at the expense of more mundane forms of sensemaking implicated in routine activities, the ambiguous status of enactment, the conflation of first-order and second-order sensemaking, and the lack of proper attention to embodied sensemaking. Copyright © 2014 John Wiley & Sons, Ltd

    Analysis of the resonant components in Bs->J/\psi\pi+\pi-

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    The decay Bs->J/\psi\pi+\pi- can be exploited to study CP violation. A detailed understanding of its structure is imperative in order to optimize its usefulness. An analysis of this three-body final state is performed using a 1.0/fb sample of data produced in 7 TeV pp collisions at the LHC and collected by the LHCb experiment. A modified Dalitz plot analysis of the final state is performed using both the invariant mass spectra and the decay angular distributions. The \pi+\pi- system is shown to be dominantly in an S-wave state, and the CP-odd fraction in this Bs decay is shown to be greater than 0.977 at 95% confidence level. In addition, we report the first measurement of the J/\psi\pi+\pi- branching fraction relative to J/\psi\phi\ of (19.79 +/- 0.47 +/- 0.52)%.Comment: 28 pages, 18 figures, updated after journal revie
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