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Nuclear Theory·nucl-th

Tuesday·December 17, 2019

14 papers—6 primary·8 cross-listed

All14Primary6Cross-lists8
  1. 01

    Calculation Binding energy for 223,225,227Ra isotopes in relativistic heavy cluster model

    Keivan Darooyi Divshali · Mohammad Reza Shojaei

    14C is a stable isotope and emitted from medium and heavy mass nuclei. The 14C result is in excellent agreement with a favored ground-state-to-ground-state transition according to the cluster model of Blendowske et al. We study Ra isotopes in relativistic core-cluster model, solve the Dirac equation with the new phenomenological potential by parametric Nikiforov-Uvarov method, and obtain wave function and binding energy.

    nucl-th0 citations
  2. 02

    Extrapolating Lattice QCD Results using Effective Field Theory

    Moti Eliyahu🇮🇱 · Betzalel Bazak🇮🇱 · Nir Barnea🇮🇱

    Lattice simulations are the only viable way to obtain ab-initio Quantum Chromodynamics (QCD) predictions for low energy nuclear physics. These calculations are done, however, in a finite box and therefore extrapolation is needed to get the free space results. Here we use nuclear Effective Field Theory (EFT), designed to provide a low energy description of QCD using baryonic degrees of freedom, to extrapolate the lattice results from finite to infinite volumes. To this end, we fit the EFT to the results calculated with nonphysical high quark masses and solve it with the stochastic variational method in both finite and infinite volumes. Moreover, we perform similar EFT calculations of the physical point and predict the finite-volume effects to be found in future Lattice QCD calculations for atomic nuclei with mass number .

    nucl-thhep-latPRC(2020)·27 citations
  3. 03

    Comparing Sinc and Harmonic Oscillator Basis for Bound States of a Gaussian Interaction

    Mamoon Sharaf · Ryan McCarty · Robert A. M. Basili · James P. Vary

    We investigate the use of the sinc collocation and harmonic oscillator bases for solving a two-particle system bound by a Gaussian potential described by the radial Schrödinger equation. We analyze the properties of the bound state wave functions by investigating where the basis-state wave functions break down and relate the breakdowns to the infrared and ultraviolet scales for both bases. We propose a correction for the asymptotic infrared region, the long range tails of the wave functions. We compare the calculated bound state eigenvalues and mean square radii obtained within the two bases. From the trends in the numerical results, we identify the advantages and disadvantages of the two bases. We find that the sinc basis performs better in our implementation for accurately computing both the deeply- and weakly-bound states whereas the harmonic oscillator basis is more convenient since the basis-state wave functions are orthogonal and maintain the same mathematical structure in both position and momentum space. These mathematical properties of the harmonic oscillator basis are especially advantageous in problems where one employs both position and momentum space. The main disadvantage of the harmonic oscillator basis as illustrated in this work is the large basis space size required to obtain accurate results simultaneously for deeply- and weakly-bound states. The main disadvantage of the sinc basis could be the numerical challenges for its implementation in a many-body application.

    nucl-th1 citation
  4. 04

    Combining phase-space and time-dependent reduced density matrix approach to describe the dynamics of interacting fermions

    Thomas Czuba🇫🇷 · Denis Lacroix🇫🇷 · David Regnier🇫🇷 · Ibrahim Ulgen🇹🇷 · Bulent Yilmaz🇹🇷

    The possibility to apply phase-space methods to many-body interacting systems might provide accurate descriptions of correlations with a reduced numerical cost. For instance, the so--called stochastic mean-field phase-space approach, where the complex dynamics of interacting fermions is replaced by a statistical average of mean-field like trajectories is able to grasp some correlations beyond the mean-field. We explore the possibility to use alternative equations of motion in the phase-space approach. Guided by the BBGKY hierarchy, equations of motion that already incorporate part of the correlations beyond mean-field are employed along each trajectory. The method is called Hybrid Phase-Space (HPS) because it mixes phase-space techniques and the time-dependent reduced density matrix approach. The novel approach is applied to the one-dimensional Fermi-Hubbard model. We show that the predictive power is improved compared to the original stochastic mean-field method. In particular, in the weak-coupling regime, the results of the HPS theory can hardly be distinguished from the exact solution even for long time.

    nucl-thcond-mat.str-elEPJA(2020)·10 citations
  5. 05

    Alpha-particle condensation: a nuclear quantum phase transition

    J.-P. Ebran🇫🇷 · M. Girod🇫🇷 · E. Khan🇫🇷 · R.D. Lasseri🇫🇷 · P. Schuck🇫🇷

    When the density of a nuclear system is decreased, homogeneous states undergo the so-called Mott transition towards clusterised states, e.g. alpha clustering, both in nuclei and in nuclear matter. Here we investigate such a quantum phase transition (QPT) by using microscopic energy density functional (EDF) calculations both with the relativistic and the Gogny approaches on the diluted O nucleus. The evolution of the corresponding single-particle spectrum under dilution is studied, and a Mott-like transition is predicted at about 1/3 of the saturation density. Complementary approaches are used in order to understand this QPT. A study of spatial localisation properties as a function of the density allows to derive a value of the Mott density in agreement with the one obtained by fully microscopic calculations in O and in nuclear matter. Moreover a study of the spontaneous symmetry breaking of the rotational group in O, down to the discrete tetrahedral one, provides further insight on the features displayed by the single-particle spectrum obtained within the EDF approach.The content of the tetrahedrally deformed A-nucleon product state in terms of spherical particle-hole configurations is investigated. Finally a study of quartet condensation and the corresponding macroscopic QPT is undertaken in infinite matter.

    nucl-thPRC(2020)·18 citations
  6. 06

    Antiproton physics

    Jean-Marc Richard🇫🇷

    We review the physics of low-energy antiprotons, and its link with the nuclear forces. This includes: antinucleon scattering on nucleons and nuclei, antiprotonic atoms and antinucleon-nucleon annihilation into mesons.

    nucl-thhep-phFront.in Phys.(2020)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE