PaperPanorama
FAQ

Nuclear Theory·nucl-th

Monday·August 2, 2021

11 papers—6 primary·5 cross-listed

All11Primary6Cross-lists5
  1. 01

    [Submitted on 29 Jul 2021]

    Residual cut-off dependence and power counting: the deuteron as a case study

    Daniel Odell🇺🇸 · Manuel Pavon Valderrama🇨🇳 · Lucas Platter🇺🇸

    Effective field theories (EFTs) require regularization and renormalization to gain predictive power. While regularization is inconsequential from the point of view of the observable predictions of EFT -- in a renormalized theory we expect predictions to be regulator-independent once the cutoff is removed -- the particular details of regulator dependence might provide interesting insights into the inner workings of an EFT. In fact, the analysis of regulator dependence has been frequently suggested as a tool to study the ordering scheme or power counting of EFTs. We show here that the choice of the regulator might impact the power law properties of the residual cutoff dependence. If this conclusion were to be confirmed, it would have consequences on the validity of this method as a tool to analyze power counting.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2107.14250 [pdf]
    Few Body Syst.(2022)·1 citation
  2. 02

    [Submitted on 29 Jul 2021]

    Effective shell-model interaction for nuclei southeast of Sn

    Z. H. Sun · G. Hagen · G. R. Jansen · T. Papenbrock

    We construct an effective shell-model interaction for the valence space spanned by single-particle neutron and single-hole proton states in Sn. Starting from chiral nucleon-nucleon and three-nucleon forces and single-reference coupled-cluster theory for Sn we apply a second similarity transformation that decouples the valence space. The particle-particle components of the resulting effective interaction can be used in shell model calculations for neutron deficient tin isotopes. The hole-hole interaction can be used to calculate the isotones south of Sn, and the full particle-hole interaction describes nuclei in the region southeast of Sn. We compute low-lying excited states in selected nuclei southeast of Sn, and find reasonable agreement with data. The presented techniques can also be applied to construct effective shell-model interactions for other regions of the nuclear chart.

    Comments:
    9 pages, 8 figures, interaction files in supplemental material
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2107.14314 [pdf]
    PRC(2021)·21 citations
  3. 03

    [Submitted on 30 Jul 2021]

    Quantum Phase Transitions within a nuclear cluster model and an effective model of QCD

    David S. Lohr-Robles🇲🇽 · Enrique Lopez-Moreno🇲🇽 · Peter O. Hess🇲🇽

    The catastrophe theory is applied to a nuclear cluster model and an effective model for QCD at low energy. The study of quantum phase transitions in the cluster model was considered in an earlier publication, but restricted to spherical clusters and on a semi-classical level. In the present contribution, we include the case of deformed clusters and determine the spectrum numerically as a function of an interaction parameter, where signatures of a quantum phase transition can be seen. It is shown that in this more complicated case, with deformation of the clusters, the catastrophe theory can be applied with some interesting consequences. A further example of a many-body problem is considered, namely an effective model of QCD, which is able to describe the low energy hadron spectrum and, when temperature is introduced, even ratios of particle-antiparticle productions. The catastrophe theory is able to provide useful information on the phase transition from a perturbative to a non-perturbative vacuum. This contributions shows the universal usefulness of catastrophe theory, while more examples of applications to different fields are mentioned in the Introduction.

    Comments:
    25 pages, 10 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2107.14379 [pdf]
    NPA(2021)·7 citations
  4. 04

    [Submitted on 30 Jul 2021]

    Toward ab initio charge symmetry breaking in nuclear energy density functionals

    Tomoya Naito🇯🇵 · Gianluca Colò🇮🇹 · Haozhao Liang🇯🇵 · Xavier Roca-Maza🇮🇹 · Hiroyuki Sagawa🇯🇵

    We propose a new approach to determine the strength of the charge symmetry breaking (CSB) term in the framework of nuclear density functional theory. It is shown that once ab initio calculations are available including accurate description of isospin symmetry breaking terms in medium and heavy nuclei, the mass difference of mirror nuclei as well as the neutron-skin thickness of doubly-closed-shell nuclei can be used to constrain the strength of the CSB interaction with an uncertainty less than , separately from other isospin symmetry breaking forces. This method opens a new vista of ab initio nuclear energy density functionals.

    Comments:
    8 pages, 3 figures, 3 tables in main text, 3 pages, 3 figures, 4 tables in supplemental material
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2107.14436 [pdf]
    PRC(2022)·21 citations
  5. 05

    [Submitted on 30 Jul 2021]

    Chiral condensates for neutron stars in hadron-quark crossover: from a parity doublet nucleon model to an NJL quark model

    Takuya Minamikawa🇯🇵 · Toru Kojo🇨🇳 · Masayasu Harada🇯🇵

    We study the chiral condensates in neutron star matter from nuclear to quark matter domain. We describe nuclear matter with a parity doublet model (PDM), quark matter with the Nambu--Jona-Lasino (NJL) model, and a matter at the intermediate density by interpolating nuclear and quark matter equations of state. The model parameters are constrained by nuclear physics and neutron star observations. Various condensates in the interpolated domain are estimated from the chemical potential dependence of the condensates at the boundaries of the interpolation. The use of the PDM with substantial chiral invariant mass ( MeV, which is favored by the neutron star observations) predicts the mild chiral restoration, and the significant chiral condensate remains to baryon density (: nuclear saturation density), smoothly approaching the NJL predictions for the color-flavor-locked phase at . The same method is applied to estimate diquark condensates, number densities of up-, down- and strange-quarks, and the lepton fraction. In our descriptions the chiral restoration in the interpolated domain proceeds with two conceptually distinct chiral restoration effects; the first is associated with the positive scalar density in a nucleon, relevant in dilute regime, and the other primarily arises from the modification of the quark Dirac sea, which is triggered by the growth of the quark Fermi sea. We discuss several qualitative conjectures to interpolate the microphysics in nuclear and quark matter.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2107.14545 [pdf]
    PRC(2021)·32 citations
  6. 06

    [Submitted on 30 Jul 2021]

    Finite-temperature infinite matter with effective-field-theory-inspired energy-density functionals

    Stefano Burrello🇩🇪 · Marcella Grasso🇫🇷

    Finite-temperature infinite matter is analyzed with the recently introduced effective-fieldtheory(EFT)-inspired YGLO (Yang-Grasso-Lacroix-Orsay) and ELYO (extended Lee-Yang, Orsay) functionals, which are designed to describe very low-density regimes in symmetric (YGLO) and in pure neutron (YGLO and ELYO) matter. The article deals with neutron matter and aims to verify whether the use of these functionals allows us to correctly incorporate finite-temperature effects. We compare our results for some relevant thermodynamical quantities with the corresponding ones computed with a chosen reference ab-initio model, namely the many-body-perturbation-theory scheme. We validate the reliability of both EFT-inspired functionals at least at rather low densities and not too high temperatures and we discuss the effects related to the effective mass. We conclude that, at the present stage, the ELYO functional, having a higher neutron effective mass around saturation (closer to ab-initio values), allows us to describe finite-temperature properties more satisfactorily, in better agreement with ab-initio predictions up to higher densities and temperatures, compared to YGLO.

    Comments:
    11 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2107.14687 [pdf]
    EPJA(2022)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE