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Determination of nuclear moments for many nuclei relies on the computation of hyperfine constants, with theoretical uncertainties directly affecting the resulting uncertainties of the nuclear moments. In this work we improve the precision…

Atomic Physics · Physics 2022-01-05 S. G. Porsev , M. S. Safronova , M. G. Kozlov

We introduce a new type of spectral density condition, that we call L^2-nuclearity. One formulation concerns lowest weight unitary representations of SL(2,R) and turns out to be equivalent to the existence of characters. A second…

Mathematical Physics · Physics 2008-11-26 Detlev Buchholz , Claudio D'Antoni , Roberto Longo

These notes survey and explore an emerging method, which we call the low-degree method, for predicting and understanding statistical-versus-computational tradeoffs in high-dimensional inference problems. In short, the method posits that a…

Statistics Theory · Mathematics 2019-07-29 Dmitriy Kunisky , Alexander S. Wein , Afonso S. Bandeira

We evaluate the Gutzwiller trace formula for the level density of classically chaotic systems by considering the level density in a bounded energy range and truncating its Fourier integral. This results in a limiting procedure which…

chao-dyn · Physics 2008-02-03 Eyal Doron

The goal of this paper is to investigate properties of clusterized nuclear matter which is believed to be present in crusts of neutron stars at subnuclear densities. It is assumed that the whole system can be represented by the set of…

Nuclear Theory · Physics 2018-04-04 Claudio Ebel , Thomas J. Bürvenich , Igor Mishustin

We consider two-nucleon scattering close to threshold. Partial-wave amplitudes are obtained by an analytic extrapolation of subthreshold reaction amplitudes calculated in a relativistic formulation of chiral perturbation theory. The…

Nuclear Theory · Physics 2015-06-12 A. M. Gasparyan , M. F. M. Lutz , E. Epelbaum

This chapter will go through the important nuclear reactions in stellar evolution and explosions, passing through the individual stellar burning stages and also explosive burning conditions. To follow the changes in the composition of…

Solar and Stellar Astrophysics · Physics 2024-04-23 Friedrich-Karl Thielemann , Thomas Rauscher

The present paper is comprised of two parts. First, we give a brief survey of the theoretical framework for microscopic nuclear structure calculations starting from a free nucleon-nucleon potential. Then, we present some selected results of…

Nuclear Theory · Physics 2007-05-23 A. Covello , L. Coraggio , A. Gargano , N. Itaco

Potential energy surfaces of even-even superheavy nuclei are evaluated within the macroscopic-microscopic approximation. A very rapidly converging analytical Fourier-type shape parametrization is used to describe nuclear shapes throughout…

Spectral clustering requires the time-consuming decomposition of the Laplacian matrix of the similarity graph, thus limiting its applicability to large datasets. To improve the efficiency of spectral clustering, a top-down approach was…

Machine Learning · Computer Science 2024-12-19 Zhichang Xu , Zhiguo Long , Hua Meng

A method for beyond-mean-field calculations based on an energy density functional is described. The main idea is to map the energy surface for the nuclear quadrupole deformation, obtained from an energy density functional at the mean-field…

Nuclear Theory · Physics 2022-12-16 J. Ljungberg , J. Boström , B. G. Carlsson , A. Idini , J. Rotureau

We present a method to calculate neutron scattering cross sections for deformed nuclei using many--body wavefunctions described with multiple reference states. Nuclear states are calculated with the generator coordinate method using a low…

Nuclear Theory · Physics 2025-09-08 J. Boström , J. Rotureau , B. G. Carlsson , A. Idini

The radiative neutron capture rates for isotopes of astrophysical interest are commonly calculated within the statistical Hauser-Feshbach reaction model. Such an approach, assuming a high level density in the compound system, can be…

Nuclear Theory · Physics 2021-04-05 K. Sieja , S. Goriely

Neutrinoless double beta decay searches are currently among the major foci of experimental physics. The observation of such a decay will have important implications in our understanding of the intrinsic nature of neutrinos and shed light on…

Nuclear Theory · Physics 2020-12-15 L. Coraggio , N. Itaco , G. De Gregorio , A. Gargano , R. Mancino , S. Pastore

We present a novel nuclear energy density functional method to calculate spectroscopic properties of atomic nuclei. Intrinsic nuclear quadrupole deformations and rotational frequencies are considered simultaneously as the degrees of freedom…

Nuclear Theory · Physics 2016-02-10 J. Luis Egido , Marta Borrajo , Tomás R. Rodríguez

It is shown that experimental values of the cross sections of inelastic low-energy neutron scattering on even-even nuclei together with the description of these cross sections in the framework of the coupled channel optical model may be…

Nuclear Theory · Physics 2010-04-12 D. A. Zaikin , I. V. Surkova

We present a graphical approach to understanding the degeneracy, density of states, and cumulative state number for some simple quantum systems. By taking advantage of basic computing operations we define a straightforward procedure for…

Quantum Physics · Physics 2014-06-30 Declan Mulhall , Matthew Moelter

We describe a new method to treat low-energy scattering problems in few-nucleon systems, and we apply it to the five-body case of neutron-alpha scattering. The method allows precise calculations of low-lying resonances and their widths. We…

Nuclear Theory · Physics 2008-11-26 Kenneth M. Nollett , Steven C. Pieper , R. B. Wiringa , J. Carlson , G. M. Hale

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…

Nuclear Theory · Physics 2022-04-27 Michał Kowal , Janusz Skalski

The calculation of a statistical measure of complexity and the Fisher-Shannon information in nuclei is carried out in this work. We use the nuclear shell model in order to obtain the fractional occupation probabilities of nuclear orbitals.…

Adaptation and Self-Organizing Systems · Physics 2009-06-18 Ricardo Lopez-Ruiz , Jaime Sanudo