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Structural phenomena in nuclei, from shell structure and clustering to superfluidity and collective rotations and vibrations, reflect emergent degrees of freedom. Ab initio theory describes nuclei directly from a fully microscopic…

Nuclear Theory · Physics 2020-04-29 M. A. Caprio , P. J. Fasano , P. Maris , A. E. McCoy , J. P. Vary

Calculations in the ab initio no-core shell model (NCSM) have conventionally been carried out using the harmonic-oscillator many-body basis. However, the rapid falloff (Gaussian asymptotics) of the oscillator functions at large radius makes…

Nuclear Theory · Physics 2014-09-02 M. A. Caprio , P. Maris , J. P. Vary

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…

Symplectic symmetry approach to clustering (SSAC) in atomic nuclei, recently proposed, is modified and further developed in more detail. It is firstly applied to the light two-cluster $^{20}$Ne + $\alpha$ system of $^{24}$Mg, the latter…

Nuclear Theory · Physics 2025-02-18 H. G. Ganev

A proton-neutron symplectic model of collective motions, based on the non-compact symplectic group $Sp(12,R)$, is introduced by considering the symplectic geometry of the two-component many-particle nuclear system. The possible classical…

Nuclear Theory · Physics 2014-10-20 H. G. Ganev

We perform no-core configuration interaction calculations for nuclei in the p-shell. We show that for typical light nuclei, a truncation on the total number of quanta in the many-body system converges much more rapidly than a full…

Nuclear Theory · Physics 2015-06-11 Pieter Maris

The ab initio symmetry-adapted no-core shell model naturally describes nuclear deformation and collectivity, and is therefore well-suited to studying the dynamics and coexistence of shapes in atomic nuclei. For the first time, we analyze…

In this work, we explore the implications of applying the formalism of symplectic geometry to quantum mechanics, particularly focusing on many-particle systems. We extend the concept of a symplectic indicator of entanglement, originally…

Quantum Physics · Physics 2025-08-20 Piotr Dulian , Adam Sawicki

We demonstrate the existence of multiple converging sequences in the ab initio no-core shell model. By examining the underlying theory of effective operators, we expose the physical foundations for the alternative pathways to convergence.…

Nuclear Theory · Physics 2008-11-26 C. Forssén , J. P. Vary , E. Caurier , P. Navrátil

No-core configuration interaction (NCCI) calculations for p-shell nuclei give rise to rotational bands, identified by strong intraband E2 transitions and by rotational patterns for excitation energies, electromagnetic moments, and…

Nuclear Theory · Physics 2020-01-28 M. A. Caprio , P. J. Fasano , J. P. Vary , P. Maris , J. Hartley

Rotational bands have been observed to emerge in ab initio no-core configuration interaction (NCCI) calculations for p-shell nuclei, as evidenced by rotational patterns for excitation energies, electromagnetic moments, and electromagnetic…

Nuclear Theory · Physics 2015-09-02 M. A. Caprio , P. Maris , J. P. Vary , R. Smith

The description of nuclei starting from the constituent nucleons and the realistic interactions among them has been a long-standing goal in nuclear physics. In addition to the complex nature of the nuclear forces, with two-, three- and…

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

Nuclear Theory · Physics 2019-10-02 Pieter Maris

An {\em ab initio} (i.e., from first principles) theoretical framework capable of providing a unified description of the structure and low-energy reaction properties of light nuclei is desirable to further our understanding of the…

Nuclear Theory · Physics 2016-04-20 S. Quaglioni , G. Hupin , A. Calci , P. Navratil , R. Roth

Ab initio calculations face the challenge of describing a complex multiscale quantum many-body system. The nuclear wave function has both strong short-range correlations and long-range contributions. Natural orbitals provide a means of…

Nuclear Theory · Physics 2017-04-11 Chrysovalantis Constantinou

Nuclei are prototypes of many-body open quantum systems. Complex aggregates of protons and neutrons that interact through forces arising from quantum chromo-dynamics, nuclei exhibit both bound and unbound states, which can be strongly…

Nuclear Theory · Physics 2015-06-04 S. Quaglioni , P. Navratil , R. Roth , W. Horiuchi

We merge two successful ab initio nuclear-structure methods, the no-core shell model (NCSM) and the multi-reference in-medium similarity renormalization group (IM-SRG) to define a new many-body approach for the comprehensive description of…

Nuclear Theory · Physics 2017-04-20 Eskendr Gebrerufael , Klaus Vobig , Heiko Hergert , Robert Roth

Results for ab initio no-core shell model calculations in a symmetry-adapted SU(3)-based coupling scheme demonstrate that collective modes in light nuclei emerge from first principles. The low-lying states of 6Li, 8Be, and 6He are shown to…

We propose a semi-empirical quark model of nucleon structure, so-called, Strongly Correlated Quark Model, SCQM, which possess the features of both non-relativistic and relativistic quark models. Based on SU(3) color symmetry it includes the…

Nuclear Theory · Physics 2025-07-01 G. Musulmanbekov

The computational cost of ab initio nuclear structure calculations is rendered particularly acute by the presence of (at least) three-nucleon interactions. This feature becomes especially critical now that many-body methods aim at extending…