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Nuclear Theory·nucl-th

Wednesday·December 25, 2019

10 papers—5 primary·5 cross-listed

All10Primary5Cross-lists5
  1. 01

    [Submitted on 23 Dec 2019]

    Dynamics of one-dimensional correlated nuclear systems within non-equilibrium Green's function theory

    Hao Lin · Hossein Mahzoon · Arnau Rios · Pawel Danielewicz

    Theory of non-equilibrium Green's function (NGF) provides a practical framework for studying quantum many-body systems out of equilibrium. Extending the previous mean field approach developed for nuclear systems in one dimension with NGF, we introduce isospin degrees of freedom to the Green's functions and incorporate short-range two-body interactions in the second-order self-consistent approximation to correlations, which represents the scattering of momentum orbitals in the Born approximation. We discuss the preparation of a finite nuclear system and examine the impact of correlations on the ground state. We also excite a finite symmetric nuclear system to oscillate in an isovector dipole mode and explore the dissipation effects in the oscillation. Finally, we demonstrate how to boost a slab to a constant and stable motion in a box, based on Galilean covariance of the theory. The studies in this paper lay the ground for the future exploration of collisions of correlated nuclear systems in one dimension.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1912.11069 [pdf]
    Annals Phys.(2020)·5 citations
  2. 02

    [Submitted on 23 Dec 2019]

    Covariant Density Functional Theory in Nuclear Physics and Astrophysics

    Junjie Yang🇺🇸 · J. Piekarewicz🇺🇸

    How does subatomic matter organize itself? Neutron stars are cosmic laboratories uniquely poised to answer this fundamental question that lies at the heart of nuclear science. Newly commissioned rare isotope facilities, telescopes operating across the entire electromagnetic spectrum, and ever more sensitive gravitational wave detectors will probe the properties of neutron-rich matter with unprecedented precision over an enormous range of densities. Yet, a coordinated effort between observation, experiment, and theoretical research is of paramount importance for realizing the full potential of these investments. Theoretical nuclear physics provides valuable insights into the properties of neutron-rich matter in regimes that are not presently accessible to experiment or observation. In particular, nuclear density functional theory is likely the only tractable framework that can bridge the entire nuclear landscape by connecting finite nuclei to neutron stars. This compelling connection is the main scope of the present review.

    Comments:
    23 pages, 5 figures. When citing this paper, please use the following: Yang J, Piekarewicz J. Covariant Density Functional Theory in Nuclear Physics and Astrophysics. Annual Review of Nuclear and Particle Science Volume 70: Submitted. DOI: 10.1146/annurev-nucl-101918-023608
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
    arXiv:
    1912.11112 [pdf]
    Ann.Rev.Nucl.Part.Sci.(2020)·41 citations
  3. 03

    [Submitted on 23 Dec 2019]

    Empirical constraints on the high-density equation of state from multi-messenger observables

    Márcio Ferreira🇵🇹 · M. Fortin🇵🇱 · Tuhin Malik🇮🇳 · B. K. Agrawal🇮🇳 · Constança Providência🇵🇹

    We search for possible correlations between neutron star observables and thermodynamic quantities that characterize high density nuclear matter. We generate a set of model-independent equations of state describing stellar matter from a Taylor expansion around saturation density. Each equation of state which is a functional of the nuclear matter parameters is thermodynamically consistent, causal and compatible with astrophysical observations. We find that the neutron star tidal deformability and radius are strongly correlated with the pressure, the energy density and the sound velocity at different densities. Similar correlations are also exhibited by a large set of mean-field models based on non-relativistic and relativistic nuclear energy density functionals. These model independent correlations can be employed to constrain the equation of state at different densities above saturation from measurements of NS properties with multi-messenger observations. In particular, precise constraints on the radius of PSR J0030+0451 thanks to NICER observations would allow to better infer the properties of matter around two times the nuclear saturation density.

    Comments:
    10 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    1912.11131 [pdf]
    PRD(2020)·29 citations
  4. 04

    [Submitted on 23 Dec 2019]

    Role of residual interaction in the relativistic description of M1 excitation

    Tomohiro Oishi · Goran Kruzic · Nils Paar

    Magnetic dipole (M1) excitation is the leading mode of multi-nucleon excitations induced by the magnetic field, and is a phenomenon of the spin-orbit (SO) splitting and residual interactions involved. In this work, we investigate the effects of the residual interactions on the M1 excitation from a novel perspective, the framework of relativistic nuclear energy-density functional (RNEDF). The relativistic Hartree-Bogoliubov (RHB) model is utilized to determine the nuclear ground state properties, while the relativistic quasi-particle random-phase approximation (RQRPA) is employed for the description of M1-excitation properties. From the analysis of M1 mode in the Ca isotope chain, role of the isovector-pseudovector (IV-PV) residual interaction is discussed. For open-shell nuclei, the pairing correlation also plays a noticeable role in the M1 mode. The experimental data on M1 mode is expected to provide a suitable reference to improve and optimize the theoretical aspects to describe the residual interactions.

    Comments:
    22 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1912.11147 [pdf]
    J.Phys.G(2020)·13 citations
  5. 05

    [Submitted on 24 Dec 2019]

    Impact of statistical uncertainties on the composition of the outer crust of a neutron star

    A. Pastore🇬🇧 · D. Neill🇬🇧 · H. Powell🇬🇧 · K. Medler🇬🇧 · C. Barton🇬🇧

    By means of Monte Carlo methods, we perform a full error analysis on the Duflo-Zucker mass model. In particular, we study the presence of correlations in the residuals to obtain a more realistic estimate of the error bars on the predicted binding energies. To further reduce the discrepancies between model prediction and experimental data we also apply a Multilayer Perceptron Neural Network. We show that the root mean square of the model further reduces of roughly 40\%. We then use the resulting models to predict the composition of the outer crust of a non accreting neutron star. We provide a first estimate of the impact of error propagation on the resulting equation of state of the system.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    1912.11365 [pdf]
    PRC(2020)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE