Symmetry-Adapted No-Core Shell Model for Light Nuclei

Launey, Kristina D.; Dytrych, Tomáš; Draayer, J. P.; Tobin, G. K.; Ferriss, M. C.; Langr, Daniel; Dreyfuss, A C; Maris, Pieter; Vary, James P.; Bahri, C.

doi:10.1142/9789814525435_0003

Cited by 3 publications

(8 citation statements)

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“…Once the γ parameter is fixed by the order of the three low-lying 0 + states in 12 C, excitation energies and other observables such as matter rms radii, electric quadrupole moments and E2 transition rates for various p-and sd-shell nuclei are found, with no parameter adjustment, to be in a remarkable agreement with the experiment [105,106,108] (see also Fig. 5 and Table 2).…”

Section: No-core Symplectic Shell Model (Ncspm) and The Elusive Hoylesupporting

confidence: 65%

“…Using the Sp(3, R) scheme, the no-core symplectic shell model (NCSpM) [105] offers N max = 12 − 24 shell-model descriptions of low-lying states in deformed sd-shell nuclei ( 20 O, 20,22 Ne, and 20,22,24 Mg) [106] and of phenomena tied to giant monopole and quadrupole resonances [107], as well as to collectivity and alpha-clustering in 12 Be [108] and 12 C, and in particular, the challenging Hoyle state and its first 2 + and 4 + excitations [105,109]. While such ultra-large model spaces remain inaccessible by ab initio shell models, the NCSpM addresses a long-standing challenge [110][111][112], namely, understanding highly-deformed spatial configurations from a shell-model perspective.…”

Section: No-core Symplectic Shell Model (Ncspm) and The Elusive Hoylementioning

confidence: 99%

“…Both mean-field and many-particle estimates demonstrate that in the helicity-transformed representation, the nucleons move in a finite-depth nonlocal potential with a reduced spin-orbit strength. Furthermore, the approximate independence of the single-nucleon spectrum in an infinite medium on the helicity transformation and the consistency of the microscopic estimates for the single-particle nuclear potentials with the Dirac-Brueckner calculations, allow one to connect the pseudo-spin symmetry to the one boson-exchange (OBEP) nature of the [106,108]. Multiplicities to distinguish repeated N (λ ω µ ω ) labels are not shown.…”

Section: Pseudo-spin Symmetry For Heavy Nucleimentioning

confidence: 99%

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Symmetry-guided large-scale shell-model theory

Launey

Dytrych

Draayer

2016

Progress in Particle and Nuclear Physics

131

173

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In this review, we present a symmetry-guided strategy that utilizes exact as well as partial symmetries for enabling a deeper understanding of and advancing ab initio studies for determining the microscopic structure of atomic nuclei. These symmetries expose physically relevant degrees of freedom that, for large-scale calculations with QCD-inspired interactions, allow the model space size to be reduced through a very structured selection of the basis states to physically relevant subspaces. This can guide explorations of simple patterns in nuclei and how they emerge from first principles, as well as extensions of the theory beyond current limitations toward heavier nuclei and larger model spaces. This is illustrated for the ab initio symmetry-adapted no-core shell model (SA-NCSM) and two significant underlying symmetries, the symplectic Sp(3, R) group and its deformation-related SU(3) subgroup. We review the broad scope of nuclei, where these symmetries have been found to play a key role -from the light p-shell systems, such as 6 Li, 8 B, 8 Be, 12 C, and 16 O, and sd-shell nuclei exemplified by 20 Ne, based on first-principle explorations; through the Hoyle state in 12 C and enhanced collectivity in intermediate-mass nuclei, within a no-core shell-model perspective; up to strongly deformed species of the rare-earth and actinide regions, as investigated in earlier studies. A complementary picture, driven by symmetries dual to Sp(3, R), is also discussed. We briefly review symmetry-guided techniques that prove useful in various nuclear-theory models, such as Elliott model, ab initio SA-NCSM, symplectic model, pseudo-SU(3) and pseudo-symplectic models, ab initio hyperspherical harmonics method, ab initio lattice effective field theory, exact pairing -plusshell model approaches, and cluster models, including the resonating-group method. Important implications of these approaches that have deepened our understanding of emergent phenomena in nuclei, such as enhanced collectivity, giant resonances, pairing, halo, and clustering, are discussed, with a focus on emergent patterns in the framework of the ab initio SA-NCSM with no a priori assumptions.

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Section: No-core Symplectic Shell Model (Ncspm) and The Elusive Hoylesupporting

confidence: 65%

Section: No-core Symplectic Shell Model (Ncspm) and The Elusive Hoylementioning

confidence: 99%

Section: Pseudo-spin Symmetry For Heavy Nucleimentioning

confidence: 99%

See 1 more Smart Citation

Symmetry-guided large-scale shell-model theory

Launey

Dytrych

Draayer

2016

Progress in Particle and Nuclear Physics

131

173

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“…In particular, we employ the NCSpM with a simple but physically-informed, schematic, many-nucleon interaction. The model has recently provided, with no parameter adjustments, no-core shell-model descriptions of low-lying states in deformed sd-shell nuclei and of phenomena tied to collectivity and alpha-clustering in 8 Be [33,34]. Here, we focus on the ground-state rotational band, the Hoyle state and its 2 + and 4…”

Section: Introductionmentioning

confidence: 99%

Understanding emergent collectivity and clustering in nuclei from a symmetry-based no-core shell-model perspective

et al. 2017

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We present a detailed discussion of the structure of the low-lying positive-parity energy spectrum of 12 C from a no-core shell-model perspective. The approach utilizes a fraction of the usual shellmodel space and extends its multi-shell reach via the symmetry-based no-core symplectic shell model (NCSpM) with a simple, physically-informed effective interaction. We focus on the ground-state rotational band, the Hoyle state and its 2 + and 4 + excitations, as well as the giant monopole 0 + resonance, which is a vibrational breathing mode of the ground state. This, in turn, allows us to address the open question about the structure of the Hoyle state and its rotational band. In particular, we find that the Hoyle state is best described through deformed prolate collective modes rather than vibrational modes, while we show that the higher-lying giant monopole 0 + resonance resembles the oblate deformation of the 12 C ground state. In addition, we identify the giant monopole 0 + and quadrupole 2 + resonances of selected light and intermediate-mass nuclei, along with other observables of 12 C, including matter rms radii, electric quadrupole moments, as well as E2 and E0 transition rates.

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“…The interaction was fitted in Ref. [1] by means of phaseequivalent transformations to the binding energies of nuclei with A ≤ 16, and it provides a good description of bindings and spectra of light nuclei without referring to three-nucleon forces [1,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. In particular, the binding energy and spectrum of exotic proton-excess nucleus 14 F have been predicted [9] in No-core Full Configuration Calculations [7] with the JISP16 N N interaction.…”

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confidence: 99%