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One of the central open problems in nuclear physics is the construction of effective interactions suitable for many-body calculations. We discuss a recently developed approach to this problem, where one starts with an effective field theory…

Nuclear Theory · Physics 2014-11-20 I. Stetcu , J. Rotureau , B. R. Barrett , U. van Kolck

We introduce a hybrid many-body approach that combines the flexibility of the No-Core Shell Model (NCSM) with the efficiency of Multi-Configurational Perturbation Theory (MCPT) to compute ground- and excited-state energies in arbitrary…

Nuclear Theory · Physics 2018-10-24 Alexander Tichai , Eskendr Gebrerufael , Klaus Vobig , Robert Roth

We report \textit{ab initio} no-core shell model (NCSM) study of $^{18-24}$Ne isotopes for energy spectra, electromagnetic properties, and point-proton radii using three realistic $NN$ interactions. We have used inside nonlocal outside…

Nuclear Theory · Physics 2023-02-08 Chandan Sarma , Praveen C. Srivastava

Large-space no-core shell model calculations have been performed for A=3-6 nuclei, using a starting-energy-independent two-body effective interaction derived by application of the Lee-Suzuki similarity transformation. This transformation…

Nuclear Theory · Physics 2008-11-26 P. Navratil , B. R. Barrett

We construct effective two-body Hamiltonians and E2 operators for the p-shell by performing $16\hbar\Omega$ ab initio no-core shell model (NCSM) calculations for A=5 and A=6 nuclei and explicitly projecting the many-body Hamiltonians and E2…

Nuclear Theory · Physics 2009-09-02 A. F. Lisetskiy , M. K. G. Kruse , B. R. Barrett , P. Navratil , I. Stetcu , J. P. Vary

We report on a novel ab initio approach for nuclear few- and many-body systems with strangeness. Recently, we developed a relevant no-core shell model technique which we successfully applied in first calculations of lightest $\Lambda$…

Nuclear Theory · Physics 2015-06-18 D. Gazda , J. Mareš , P. Navrátil , R. Roth , R. Wirth

Different techniques for calculating effective operators within the framework of the shell model using the same effective interaction and the same excitation spaces are presented. Starting with the large-basis no-core approach, we compare…

Nuclear Theory · Physics 2008-11-26 M. Thoresen , P. Navratil , B. R. Barrett

The nuclear shell model is one of the successful models in theoretical understanding of nuclear structure. If a convenient effective interaction can be found between nucleons, various observables such as energies of nuclear states are…

Nuclear Theory · Physics 2020-01-24 Serkan Akkoyun , Nadjet Laouet , Fatima Benrachi

We perform \textit{ab initio} no-core shell-model calculations for $A=18$ and $19$ nuclei in a $4\hbar\Omega$, or $N_{\rm max}=4$, model space by using the effective JISP16 and chiral N3LO nucleon-nucleon potentials and transform the…

Nuclear Theory · Physics 2015-06-09 E. Dikmen , A. F. Lisetskiy , B. R. Barrett , P. Maris , A. M. Shirokov , J. P. Vary

Nuclear structure and reaction theory is undergoing a major renaissance with advances in many-body methods, strong interactions with greatly improved links to Quantum Chromodynamics (QCD), the advent of high performance computing, and…

No-Core Gamow Shell Model (NCGSM) is applied for the first time to study selected well-bound and unbound states of helium isotopes. This model is formulated on the complex energy plane and, by using a complete Berggren ensemble, treats…

Nuclear Theory · Physics 2015-06-12 G. Papadimitriou , J. Rotureau , N. Michel , M. Płoszajczak , B. R. Barrett

We study the efficacy of a new ab initio framework that combines the symmetry-adapted (SA) no-core shell-model approach with the resonating group method (RGM) for unified descriptions of nuclear structure and reactions. We obtain ab initio…

We present first ab initio no-core shell model (NCSM) calculations using similarity renormalization group (SRG) transformed chiral two-nucleon (NN) plus three-nucleon (3N) interactions for nuclei throughout the p-shell, particularly 12-C…

Nuclear Theory · Physics 2011-08-22 Robert Roth , Joachim Langhammer , Angelo Calci , Sven Binder , Petr Navrátil

We report on the computational characteristics of ab initio nuclear structure calculations in a symmetry-adapted no-core shell model (SA-NCSM) framework. We examine the computational complexity of the current implementation of the SA-NCSM…

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

Background: Effective interactions, either derived from microscopic theories or based on fitting selected properties of nuclei in specific mass regions, are widely used inputs to shell-model studies of nuclei. Until recently, most…

Nuclear Theory · Physics 2015-06-17 Naofumi Tsunoda , Kazuo Takayanagi , Morten Hjorth-Jensen , Takaharu Otsuka

In this review, we discuss recent applications of the ab initio symmetry-adapted no-core shell-model (SA-NCSM) theory for study and prediction of structure and reactions of stable and unstable nuclei from light to medium mass range. We…

We calculate the low-lying spectra of heavy tin isotopes from A=120 to A=130 using the 2s1d0g_{7/2}0h_{11/2} shell to define the model space. An effective interaction has been derived using 132Sn as closed core employing perturbative…

Nuclear Theory · Physics 2009-10-30 A. Holt , T. Engeland , M. Hjorth-Jensen , E. Osnes

An ensemble of neural networks is employed to extrapolate no-core shell model (NCSM) results to infinite model space for light nuclei. We present a review of our neural network extrapolations of the NCSM results obtained with the Daejeon16…

Nuclear Theory · Physics 2025-12-22 Aleksandr Mazur , Roman Sharypov , Andrey Shirokov

An overview of the ab initio no-core shell model is presented. Recent results for light nuclei obtained with the chiral two-nucleon and three-nucleon interactions are highlighted. Cross section calculations of capture reactions important…

Nuclear Theory · Physics 2007-11-20 Petr Navratil