Nuclear Theory·nucl-th

Wednesday·April 27, 2022

11 papers—4 primary·7 cross-listed

01
Ab-initio QCD calculations impact the inference of the neutron-star-matter equation of state
Tyler Gorda🇩🇪 · Oleg Komoltsev🇳🇴 · Aleksi Kurkela🇳🇴
We demonstrate that ab-initio calculations in QCD at high densities offer significant and nontrivial information about the equation of state of matter in the cores of neutron stars, going beyond that which is obtainable from current astrophysical observations. We do so by extrapolating the equation of state to neutron-star densities using a Gaussian process and conditioning it sequentially with astrophysical observations and QCD input. Using our recent work, imposing the latter does not require an extrapolation to asymptotically high density. We find the QCD input to be complementary to the astrophysical observations, offering strong additional constraints at the highest densities reached in the cores of neutron stars; with the QCD input, the equation of state is no longer prior dominated at any density. The QCD input reduces the pressure and speed of sound at high densities, and it predicts that binary collisions of equal-mass neutron stars will produce a black hole with greater than $95%$ ( $68%$ ) credence for masses $M \geq 1.38 M_{⊙}$ ( $M \geq 1.25 M_{⊙}$ ). We provide a Python implementation of the QCD likelihood function so that it can be conveniently used within other inference setups.
nucl-thastro-ph.HEhep-phApJ(2023)·174 citations
02
Symmetry restoration methods
J. M. Yao
Symmetry techniques based on group theory play a prominent role in the analysis of nuclear phenomena, and in particular in the understanding of observed regular patterns in nuclear spectra and selection rules for electromagnetic transitions. A variety of symmetry-based nuclear models have been developed in nuclear physics, providing efficient tools of choice to interpret nuclear spectroscopic data. This chapter provides a pedagogical introduction to the basic idea of symmetry-breaking mechanism and symmetry-restoration methods in modeling atomic nuclei.
nucl-th7 citations
03
The finite range simple effective interaction including tensor terms
P. Bano · X. Viñas · T. R. Routray · M. Centelles · M. Anguiano · L. M. Robledo
The prediction of single particle level crossing phenomenon between $2 p_{3/2}$ and $1 f_{5/2}$ orbitals in $N i$ - and $C u$ -isotopic chains by the finite range simple effective interaction without requiring the tensor part is discussed. In this case the experimentally observed crossing could be studied as a function of nuclear matter incompressibility, $K (ρ_{0})$ . The estimated crossing for the neutron number $N$ =46 could be reproduced by the equation of state corresponding to $K (ρ_{0})$ =240 MeV. However, the observed proton gaps between the $1 h_{11/2}$ and $1 g_{7/2}$ shells in $S n$ and $S b$ isotopic chain, and the neutron gaps between the $1 i_{13/2}$ and $1 h_{9/2}$ shells in $N$ =82 isotones, as well as the shell closure properties at $N$ =28 require explicit consideration of a tensor part as the central contribution is not enough to initiate the required level splittings.
nucl-thPRC(2022)·10 citations
04
The Fission Barrier of Heaviest Nuclei From a Macroscopic-Microscopic Perspective
Michał Kowal · Janusz Skalski
The concept of fission barrier - a parameter which enters in quantitative estimates of various observables related to nuclear fission - is presented from the point of view of theory based on the picture of nuclear deformation and energy dependent on it. We describe the macroscopic-microscopic method of calculating energy landscapes which is simpler than the selfconsistent mean field approach, and, due to its two-component nature, seems to be easier to adjust to experimental data. We present some models and methods used to find the fission saddles. For the purpose of illustration, we present results on fission barriers in actinides and superheavy nuclei, obtained within one macroscopic-microscopic model. We discuss comparisons with results of other models, including some of the mean-field type.
nucl-th1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Ab-initio QCD calculations impact the inference of the neutron-star-matter equation of state

Symmetry restoration methods

The finite range simple effective interaction including tensor terms

The Fission Barrier of Heaviest Nuclei From a Macroscopic-Microscopic Perspective

Affiliations