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Nuclear Theory·nucl-th

Wednesday·January 24, 2024

8 papers—5 primary·3 cross-listed

All8Primary5Cross-lists3
  1. 01

    Universal relations for anisotropic interacting quark stars

    Juan M. Z. Pretel🇧🇷 · Chen Zhang🇨🇳

    Interacting quark stars, which are entirely composed of interacting quark matter including perturbative QCD corrections and color superconductivity, can meet constraints from various pulsar observations. In realistic scenarios, pressure anisotropies are expected in the star's interior. Recently, the stellar structural properties of anisotropic interacting quark stars have been investigated. In this study, we further explore the universal relations (URs) related to the moment of inertia , tidal deformability , compactness , and the -mode nonradial pulsation frequency for such stars. Our results reveal that these approximate URs generally hold, being insensitive to both the EOS variations as well as to the presence of anisotropy. In contrast to previous studies on anisotropic neutron stars, we find that more positive anisotropy tends to enhance the and URs, but weakens the UR. For all the URs involving -mode frequency, we find that they are enhanced by the inclusion of anisotropy (whether positive or negative). Utilizing these URs and the tidal deformability constraint from the GW170817 event, we put limits on the structural properties of isotropic and anisotropic quark stars, such as the moment of inertia , the canonical radius and the canonical -mode frequency , all of which are very different compared to those of neutron stars.

    nucl-thastro-ph.HEgr-qchep-phJCAP(2024)·21 citations
  2. 02

    Uncertainty quantification in the machine-learning inference from neutron star probability distribution to the equation of state

    Yuki Fujimoto🇺🇸 · Kenji Fukushima🇯🇵 · Syo Kamata🇯🇵 · Koichi Murase🇯🇵

    We discuss the machine-learning inference and uncertainty quantification for the equation of state (EoS) of the neutron star (NS) matter directly using the NS probability distribution from the observations. We previously proposed a prescription for uncertainty quantification based on ensemble learning by evaluating output variance from independently trained models. We adopt a different principle for uncertainty quantification to confirm the reliability of our previous results. To this end, we carry out the MC sampling of data to infer an EoS and take the convolution with the probability distribution of the observational data. In this newly proposed method, we can deal with arbitrary probability distribution not relying on the Gaussian approximation. We incorporate observational data from the recent multimessenger sources including precise mass measurements and radius measurements. We also quantify the importance of data augmentation and the effects of prior dependence.

    nucl-thastro-ph.HEhep-phPRD(2024)·41 citations
  3. 03

    Converging Many-Body Perturbation Theory for Ab Initio Nuclear Structure: II. Brillouin-Wigner Perturbation Series for Open-Shell Nuclei

    Zhen Li🇫🇷 · Nadezda A. Smirnova🇫🇷

    Brillouin-Wigner (BW) perturbation theory is developed for both ground and excited states of open-shell nuclei. We show that with optimal partitioning of the many-body Hamiltonian proposed earlier by the authors [Z. Li and N. Smirnova, arXiv:2306.13629], one can redefine the BW perturbation series for a given state of the effective Hamiltonian in a small P-space to be converging under the condition that the energy of this state is below the lowest eigenvalue of the Hamiltonian matrix block belonging to the complement of the P-space, characterized by the same good quantum numbers as the state under consideration. Specifically, the BW perturbative calculations for the lowest states are always converging due to the variational principle. This property does hold for both soft and hard internucleon interactions in the harmonic oscillator basis. To illustrate this method and check the convergence behavior, we present numerical studies of low-energy spectra of Li using the Daejeon16 and bare N3LO potentials.

    nucl-thPRC(2024)·1 citation
  4. 04

    Description of the odd No nuclei using Skyrme functionals with modified spin-spin interaction

    N. Lyutorovich

    The Skyrme energy-density functionals with modified spin-spin interaction and pairing strength are used for description of the No, No, and No excited states. The results of the HFB and cranked HFB calculations taking into account the blocking effect are in reasonable agreement with the available data. For many states, including rotational and three-quasiparticle states, the results of self-consistent calculations were obtained for the first time.

    nucl-thIJMPE(2024)·0 citations
  5. 05

    Modern nuclear and astrophysical constraints of dense matter in a renormalized chiral approach

    Rajesh Kumar🇺🇸 · Yuhan Wang🇺🇸 · Nikolas Cruz Camacho🇺🇸 · Arvind Kumar🇮🇳 · Jacquelyn Noronha-Hostler🇺🇸 · Veronica Dexheimer🇺🇸

    We explore the Quantum Chromodynamics (QCD) phase diagram's complexities, including quark deconfinement transitions, liquid-gas phase changes, and critical points, using the chiral mean-field (CMF) model that is able to capture all these features. We introduce a vector meson renormalization within the CMF framework, enabling precise adjustments of meson masses and coupling strengths related to vector meson interactions. Performing a new fit to the deconfinement potential, we are able to replicate recent lattice QCD results, low energy nuclear physics properties, neutron star observational data, and key phase diagram features as per modern constraints. This approach enhances our understanding of vector mesons' roles in mediating nuclear interactions and their impact on the equation of state, contributing to a more comprehensive understanding of the QCD phase diagram and its implications for nuclear and astrophysical phenomena.

    nucl-thastro-ph.HEhep-phPRD(2024)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE