English
Related papers

Related papers: Parity-Projected Shell Model Monte Carlo Level Den…

200 papers

We utilize the Shell Model Monte Carlo (SMMC) method to study the structure of rare earth nuclei. This work demonstrates the first systematic ``full oscillator shell plus intruder'' calculations in such heavy nuclei. Exact solutions of a…

Nuclear Theory · Physics 2009-10-31 J. A. White , S. E. Koonin , D. J. Dean

The shell model Monte Carlo (SMMC) method is a powerful method for calculating exactly (up to statistical errors) thermal observables and statistical properties of atomic nuclei. However, its application has been limited by a sign problem…

Nuclear Theory · Physics 2025-01-08 Y. Alhassid , P. Fanto , C. Özen

The interplay of pairing is explored for the spectral statistics of nuclear systems with emphasis on the nearest neighbor spacing distributions by employing the kernel density and maximum likelihood estimation techniques. Different…

Nuclear Theory · Physics 2013-06-25 H. Sabri , B. Rashidian Maleki , J. Fouladi , N. Fouladi , M. A. Jafarizadeh

The level schemes and transition rates {\em B}({\em E}2;$\uparrow$) of eve-even $^{48-56}$Ti isotopes were studied by performing large-scale shell model calculations with FPD6 and GXPF1 effective interactions. Excellent agreement were…

Nuclear Theory · Physics 2015-06-26 F. A. Majeed , A. A. Auda

We use shell model techniques in the complete pf shell to study pair correlations in nuclei. Particular attention is paid to the competition of isoscalar and isovector proton-neutron pairing modes which is investigated in the odd-odd N=Z…

Nuclear Theory · Physics 2009-10-31 G. Martinez-Pinedo , K. Langanke , P. Vogel

We introduce a novel method to obtain level densities in large-scale shell-model calculations. Our method is a stochastic estimation of eigenvalue count based on a shifted Krylov-subspace method, which enables us to obtain level densities…

Microscopic calculations show a strong parity dependence of the nuclear level density at low excitation energy of a nucleus. Previously, this dependence has either been neglected or only implemented in the initial and final channels of…

Information on level density for nuclei with mass numbers A = 20 - 250 is deduced from discrete low-lying levels and neutron resonance data. The odd-mass nuclei exhibit in general 4 - 7 times the level density found for its neighboring…

Nuclear Experiment · Physics 2009-10-31 M. Guttormsen , M. Hjorth-Jensen , E. Melby , J. Rekstad , A. Schiller , S. Siem

The structure of $^{35,37,39}$S isotopes is described by performing comprehensive shell model calculations with SDPF-U and SDPFMW interactions. Protons and neutrons are restricted to the $sd$-shell for $N < 20$, neutrons start to fill the…

Nuclear Theory · Physics 2017-03-08 Archana Saxena , P. C. Srivastava , Jorge G. Hirsch , V. K. B. Kota , M. J. Ermamatov

A comprehensive test of level density models for explaining the decay of excited compound nuclei, 54 Mn, 56 Fe, 58 Co, 60 Ni, 61 Ni and 63 Cu, in the energy range of 28 - 36 MeV has been performed. The compound nuclei of interest in the…

Simple methods in the frame work of the broken pair model have been worked out for odd-odd nuclei. The reliability of the model has been tested by reproducing the shell model results of limiting cases in which the broken pair model exactly…

Nuclear Theory · Physics 2007-07-01 I. M. Hamammu , S. Haq , J. M. Eldahomi

The configuration-interaction shell model approach provides an attractive framework for the calculation of nuclear level densities in the presence of correlations, but the large dimensionality of the model space has hindered its application…

Nuclear Theory · Physics 2016-01-05 Y. Alhassid , G. F. Bertsch , C. N. Gilbreth , H. Nakada , C. Özen

The information on the symmetry energy and its density dependence is deduced by comparing the available data on the electric dipole polarizability $\alpha_D$ of ${}^{68}$Ni, ${}^{120}$Sn, and ${}^{208}$Pb with the predictions of the Random…

Nuclear Theory · Physics 2015-12-10 X. Roca-Maza , X. Viñas , M. Centelles , B. K. Agrawal , G. Colo' , N. Paar , J. Piekarewicz , D. Vretenar

Astrophysical reaction rates are sensitive to the parity distribution at low excitation energies. We combine a formula for the energy-dependent parity distribution with a microscopic-macroscopic nuclear level density. This approach…

Shell-model calculations with density-dependent interactions are performed to investigate $pf$-shell nuclei, examining the ground-state energies, low-lying spectra, and $E2$ transition probabilities. The density-dependent terms in the…

Nuclear Theory · Physics 2026-01-26 K. Yoshinaga , N. Shimizu , T. Nakatsukasa

The nuclear level densities and level-density parameters in fissioning nuclei at their saddle points of fission barriers - $a_{f}$, as well as those for neutron - $a_{n}$, proton - $a_{p}$ , and $\alpha$-particle - $a_{\alpha}$ emission…

Nuclear Theory · Physics 2021-08-31 A. Rahmatinejad , T. M. Shneidman , G. Adamian , N. V. Antonenko , P. Jachimowicz , M. Kowal

We have developed an efficient isospin projection method in the shell model Monte Carlo approach for isospin-conserving Hamiltonians. For isoscalar observables this projection method has the advantage of being exact sample by sample. The…

Nuclear Theory · Physics 2008-12-18 H. Nakada , Y. Alhassid

Spin and parity dependent nuclear level densities (NLDs) are obtained for configuration interaction shell model using a numerically efficient spectral distribution method. The calculations are performed for $^{24}$Na, $^{25,26,27}$Mg nuclei…

Nuclear Theory · Physics 2024-02-15 T. Ghosh , Sangeeta , B. Maheshwari , G. Saxena , B. K. Agrawal

The spin and parity dependent nuclear level densities (NLD) are calculated for medium-heavy nuclei using shell model techniques. The NLD are used to calculate cross sections and reaction rates of interest for nuclear astrophysics and…

Nuclear Theory · Physics 2018-01-17 Mihai Horoi , Jayani Dissanayake

Electron-capture rates at different density and temperature conditions are evaluated for a set of pf-shell nuclei representative of the constituents in presupernova formations. The nuclear structure part of the problem is described within a…

Nuclear Theory · Physics 2013-04-09 P. Sarriguren