68 research outputs found

    Features of exceptional points and the continuum spectroscopy

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    We discuss observable features of exceptional points and the resonance spectroscopy of 16^{16}Ne using the Shell Model Embedded in the Continuum.Comment: 10 pages, 4 figures Zakopane Conference on Nuclear Physics, September 1-7, 2008, Zakopane, Polan

    Structure of many-body continuum states in the proximity of exceptional points

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    We demonstrate existence of exceptional points in many-body scattering continuum of atomic nucleus and discuss their salient effects on the example of one-nucleon spectroscopic factors.Comment: 5 pages, 4 figure

    On the origin of nuclear clustering

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    Clustering is one of the most complex phenomena known to the structure of atomic nuclei. A comprehensive description of this ubiquitous phenomenon goes beyond standard shell model and cluster model frameworks. We argue that clustering is a consequence of an openness of the nuclear many-body system. To illustrate this point, we study the near-threshold behavior of exceptional points in ^16 Ne and ^24 S.Comment: Proceedings "Frontier Issues in Physics of Exotic Nuclei" (YKIS2011/DCEN2011), 14 pages, 9 figure

    Unexpected features of quantum degeneracies in a pairing model with two integrable limits

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    The evolution pattern of level crossings and exceptional points is studied in a non-integrable pairing model with two different integrable limits. One of the integrable limits has two independent parameter-dependent integrals of motion. We demonstrate, and illustrate in our model, that quantum integrability of a system with more than one parameter-dependent integral of motion is always signaled by level crossings of a complex-extended Hamiltonian. We also find that integrability implies a reduced number of exceptional points. Both properties could uniquely characterize quantum integrability in small Hilbert spaces.Comment: 4 pages, 2 figure

    Pushback: Title VII Takes on Hobby Lobby

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    In Hobby Lobby, the U.S. Supreme Court decided that a for-profit corporation could avoid the requirement under the Affordable Care Act that it pay for coverage of female contraception in the employee health plan due to the employer’s religious objections to birth control. In so deciding, the Court allowed the employer to discriminate against its female employees in their employee benefits. Such a decision raises the possibility of a claim of sex discrimination by the corporation’s female employees under Title VII. This article explores the main issues and pitfalls in such a claim. The two main issues with the possible claim described here is with the Title VII requirements of a proper comparator and an adverse employment action. This article asserts that the proper comparator to female birth contraceptives is not male contraceptives but preventive treatments. On the adverse employment action element, this article finds that there presently is no adverse employment action, defeating the possible claim, because Hobby Lobby requires contraceptive coverage by the insurer when the employer has religious objections. The employee does not have to pay out of pocket. But if the ACA and with it the contraceptive mandate is repealed, as the current Congress and President have repeatedly threatened, employees could suffer a material loss when they have to pay out of pocket for birth control. At that point, a Title VII claim would be viable

    Continuum Coupling Effects in Spectra of Mirror Nuclei and Binding Systematics

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    Continuum-coupling correction to binding energies in neutron rich oxygen and fluorine isotopes and to excitation energies of 2+ states in 36Ca and 36S mirror nuclei are studied using the real-energy continuum shell model.Comment: Proc. XXX Mazurian Lakes Conference on Physics: Nuclear Physics and Fundamental Processes 15 pages, 5 figure

    Shell Model Embedded in the Continuum for Binding Systematics in Neutron-Rich Isotopes of Oxygen and Fluor

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    Continuum coupling correction to binding energies in the neutron rich oxygen and fluorine isotopes is studied using the Shell Model Embedded in the Continuum. We discuss the importance of different effects, such as the position of one-neutron emission threshold, the effective interaction or the number of valence particles on the magnitude of this correction

    Statistical aspects of nuclear coupling to continuum

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    Various global characteristics of the coupling between the bound and scattering states are explicitly studied based on realistic Shell Model Embedded in the Continuum. In particular, such characteristics are related to those of the scattering ensemble. It is found that in the region of higher density of states the coupling to continuum is largely consistent with the statistical model. However, assumption of channel equivalence in the statistical model is, in general, violated

    Microscopic Description of Nuclear Fission Dynamics

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    We discuss possible avenues to study fission dynamics starting from a time-dependent mean-field approach. Previous attempts to study fission dynamics using the time-dependent Hartree-Fock (TDHF) theory are analyzed. We argue that different initial conditions may be needed to describe fission dynamics depending on the specifics of the fission phenomenon and propose various approaches towards this goal. In particular, we provide preliminary calculations for studying fission following a heavy-ion reaction using TDHF with a density contraint. Regarding prompt muon-induced fission, we also suggest a new approach for combining the time-evolution of the muonic wave function with a microscopic treatment of fission dynamics via TDHF
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