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Nuclear Theory·nucl-th

Thursday·November 8, 2018

12 papers—7 primary·5 cross-listed

All12Primary7Cross-lists5
  1. 01

    [Submitted on 7 Nov 2018]

    Matrix Model of Strength Distribution: Extension and Phase Transition

    Arun Kingan · Larry Zamick

    In this work we extend a previous study of matrix models of strength distributions. We still retain the nearest neighbor coupling mode but we extend the values the coupling parameter v. We consider extremes, from very smal v to very large v. We first use the same transiiton operator as before \textless{}n T(n+1)\textgreater{} =constat(=1). For this case we get an exponential decreasefor small v but we get a phase transition beyond v=10. In that case we get an even-odd effect-separate exponentials for even n and for odd n. We now also consider also the dipole choice--where \textless{}nT(n+1)\textgreater{} = .

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Quantum Physics (quant-ph)
    arXiv:
    1811.02562 [pdf]
    IJMPE(2018)·6 citations
  2. 02

    [Submitted on 7 Nov 2018]

    Microscopic description of the pygmy dipole resonance in neutron-rich Ca isotopes

    N. N. Arsenyev🇷🇺 · A. P. Severyukhin🇷🇺 · V. V. Voronov🇷🇺 · Nguyen Van Giai🇫🇷

    We study the effects of the phonon-phonon coupling on the low-energy electric dipole response within a microscopic model based on an effective Skyrme interaction. The finite rank separable approach for the quasiparticle random phase approximation is used. Choosing as an example the isotopic chain of Calcium, we show the ability of the method to describe the low-energy strength distribution. With one and the same set of parameters we describe available experimental data for Ca and predict the electric dipole strength function for Ca.

    Comments:
    5 pages, 5 figures, proceedings of International Conference on Nuclear Structure and Related Topics (NSRT18), June 3-9 2018, Burgas, Bulgaria
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1811.02779 [pdf]
    EPJ Web Conf.(2018)·2 citations
  4. 04

    [Submitted on 7 Nov 2018]

    Two-nucleon emitters within a pseudostate approach

    J. Casal · J. Gómez-Camacho

    A method to identify and characterize three-body resonances in a discrete basis is discussed in the context of two-nucleon emitters. For this purpose, a resonance operator is introduced and diagonalized in a basis of energy pseudostates within the hyperspherical formalism. Then, the energy and width of the resonance are obtained from its time dependence. The approach is illustrated for Be ().

    Comments:
    4 pages, 2 figures; proceedings of the FB22 international conference (amended references)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1811.02826 [pdf]
    Springer Proc.Phys.(2020)·0 citations
  5. 05

    [Submitted on 7 Nov 2018]

    Temperature dependence of the volume and surface contributions to the nuclear symmetry energy within the coherent density fluctuation model

    A.N. Antonov · D.N. Kadrev · M.K. Gaidarov · P. Sarriguren · E. Moya de Guerra

    The temperature dependence of the volume and surface components of the nuclear symmetry energy (NSE) and their ratio is investigated in the framework of the local density approximation (LDA). The results of these quantities for finite nuclei are obtained within the coherent density fluctuation model (CDFM). The CDFM weight function is obtained using the temperature-dependent proton and neutron densities calculated through the HFBTHO code that solves the nuclear Skyrme-Hartree-Fock-Bogoliubov problem by using the cylindrical transformed deformed harmonic-oscillator basis. We present and discuss the values of the volume and surface contributions to the NSE and their ratio obtained for the Ni, Sn, and Pb isotopic chains around double-magic Ni, Sn, and Pb nuclei. The results for the -dependence of the considered quantities are compared with estimations made previously for zero temperature showing the behavior of the NSE components and their ratio, as well as with the available experimental data. The sensitivity of the results on various forms of the density dependence of the symmetry energy is studied. We confirm the existence of `kinks' of these quantities as functions of the mass number at MeV for the double closed-shell nuclei Ni and Sn and the lack of `kinks' for the Pb isotopes, as well as the disappearance of these kinks as the temperature increases.

    Comments:
    14 pages, 12 figures, 1 table, accepted for publication in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1811.02897 [pdf]
    PRC(2018)·19 citations
  6. 06

    [Submitted on 7 Nov 2018]

    Phase transitions and Bose-Einstein condensation in alpha-nucleon matter

    L. M. Satarov · I. N. Mishustin · A. Motornenko · V. Vovchenko · M. I. Gorenstein · H. Stoecker

    The equation of state and phase diagram of isospin-symmetric chemically equilibrated mixture of alpha particles and nucleons are studied in the mean-field approximation. The model takes into account the effects of Fermi and Bose statistics for nucleons and alphas, respectively. We use Skyrme-like parametrization of the mean-field potentials as functions of partial densities, which contain both attractive and repulsive terms. Parameters of these potentials are chosen by fitting known properties of pure nucleon- and pure alpha matter at zero temperature. The sensitivity of results to the choice of the alpha-nucleon attraction strength is investigated. The phase diagram of the alpha-nucleon mixture is studied with a special attention paid to the liquid-gas phase transitions and the Bose-Einstein condensation of alpha particles. We have found two first-order phase transitions, stable and metastable, which differ significantly by the fractions of alpha particles. It is shown that states with alpha condensate are metastable.

    Comments:
    28 pages, 10 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1811.02924 [pdf]
    PRC(2019)·19 citations
  7. 07

    [Submitted on 7 Nov 2018]

    Towards a novel energy density functional for beyond-mean-field calculations with pairing and deformation

    T. Haverinen🇫🇮 · M. Kortelainen🇫🇮 · J. Dobaczewski🇫🇮 · K. Bennaceur🇫🇷

    We take an additional step towards the optimization of the novel finite-range pseudopotential at constrained Hartree-Fock-Bogolyubov level and implement an optimization procedure within an axial code using harmonic oscillator basis. We perform the optimization using three different numbers of the harmonic oscillator shells. We apply the new parameterizations in the O-Kr part of the nuclear chart and isotopic chain of Sn, and we compare the results with experimental values and those given by a parameterization obtained using a spherical code.

    Comments:
    Contribution to the proceedings of the Zakopane Conference on Nuclear Physics, August 26 - September 2, 2018
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1811.02997 [pdf]
    Acta Phys.Polon.B(2019)·1 citation

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first authorsco-authorsvia INSPIRE