Shell model Monte Carlo methods

Koonin, S. E.; Dean, D. J.; Langanke, K.

doi:10.1016/s0370-1573(96)00017-8

Cited by 463 publications

(475 citation statements)

References 105 publications

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“…Since then, improvements in the weak rates have been focused on the description of the nuclear-structure aspect of the problem. Different approaches are found in the literature and can be roughly divided into shell model (SM) [7][8][9][10] and proton-neutron quasiparticle random-phase approximation (QRPA) [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] categories. Hybrid models using RPA methods on top of a temperature-dependent description of the parent nucleus using a shell-model Monte Carlo approach have also been developed to calculate stellar EC rates [26].…”

Section: Introductionmentioning

confidence: 99%

Contribution of excited states to stellar weak-interaction rates in odd-Anuclei

Sarriguren¹

2016

Phys. Rev. C

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Weak-interaction rates, including β decay and electron capture, are studied in several odd-A nuclei in the pf -shell region at various densities and temperatures of astrophysical interest. Special attention is paid to the relative contribution to these rates of thermally populated excited states in the decaying nucleus. The nuclear structure involved in the weak processes is studied within a quasiparticle random-phase approximation with residual interactions in both particle-hole and particle-particle channels on top of a deformed Skyrme Hartree-Fock mean field with pairing correlations. In the range of densities and temperatures considered, it is found that the total rates do not differ much from the rates of the ground state fully populated. In any case, the changes are not larger than the uncertainties due to the nuclear-model dependence of the rates.

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Section: Introductionmentioning

confidence: 99%

Contribution of excited states to stellar weak-interaction rates in odd-Anuclei

Sarriguren¹

2016

Phys. Rev. C

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“…Correlation effects can be taken into account in the context of the configuration-interaction (CI) shell model approach, but the size of the required model space in heavy nuclei is prohibitively large for direct diagonalization of the CI shell model Hamiltonian. This limitation can be overcome in part by using the shell model Monte Carlo (SMMC) method [1][2][3][4][5]. The SMMC method enables the calculation of statistical nuclear properties, and in particular of level densities, in very large model spaces [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Nuclear state densities of odd-mass heavy nuclei in the shell model Monte Carlo approach

2015

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The shell model Monte Carlo (SMMC) approach enables the microscopic calculation of nuclear state densities in model spaces that are many orders of magnitude larger than those that can be treated by conventional diagonalization techniques. However, it has been difficult to calculate accurate state densities of odd-mass heavy nuclei as a function of excitation energy. This is because of a sign problem that arises from the projection on an odd number of particles at low temperatures, making it difficult to calculate accurate ground-state energies of odd-mass nuclei in direct Monte Carlo calculations. Here we extract the ground-state energy from a one-parameter fit of the SMMC thermal energy to the thermal energy that is determined from experimental data. This enables us to calculate the state densities of the odd-even isotopes 149−155 Sm and 143−149 Nd as a function of excitation energy. We find close agreement with state densities extracted from experimental data. Our results demonstrate that the state densities of the odd-mass samarium and neodymium isotopes can be consistently reproduced using the same Hamiltonian of the neighboring even-mass isotopes within the configuration-interaction shell model approach.

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“…As for approaches other than the pn-QRPA, these can be found in, e.g., Refs. [47][48][49][50][51] (the shell model), [52] (the projected HFB), [53] (the microscopic interacting boson model), and [54] (the energy-density functional-plus-generator-coordinate method).…”

Section: Introductionmentioning

confidence: 99%

Overlap of quasiparticle random-phase approximation states based on ground states of different nuclei: Mathematical properties and test calculations

Terasaki

2013

Phys. Rev. C

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The overlap of the excited states in quasiparticle random-phase approximation (QRPA) is calculated to simulate the overlap of the intermediate nuclear states of the double-β decay. Our basic idea is to use the like-particle QRPA with the aid of the closure approximation and calculate the overlap as rigorously as possible by making use of the explicit equation of the QRPA ground state. The formulation is shown in detail, and the mathematical properties of the overlap matrix are investigated. Two test calculations are performed for relatively light nuclei with the Skyrme and volume δ-pairing energy functionals. The validity of the truncations used in the calculation is examined and confirmed.

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Shell model Monte Carlo methods

Cited by 463 publications

References 105 publications

Contribution of excited states to stellar weak-interaction rates in odd-Anuclei

Contribution of excited states to stellar weak-interaction rates in odd-Anuclei

Nuclear state densities of odd-mass heavy nuclei in the shell model Monte Carlo approach

Overlap of quasiparticle random-phase approximation states based on ground states of different nuclei: Mathematical properties and test calculations

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