Browsing by Author "Bertsch, George F."
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Conference Object Citation - WoS: 0Citation - Scopus: 0Level Densities of Heavy Nuclei in the Shell Model Monte Carlo Approach(EDP Sciences, 2016) Alhassid, Yoram; Bertsch, George F.; Gilbreth, Christopher N.; Nakada, Hitoshi; Özen, CemNuclear level densities are necessary input to the Hauser-Feshbach theory of compound nuclear reactions. However the microscopic calculation of level densities in the presence of correlations is a challenging many-body problem. The configuration-interaction shell model provides a suitable framework for the inclusion of correlations and shell effects but the large dimensionality of the many-particle model space has limited its application in heavy nuclei. The shell model Monte Carlo method enables calculations in spaces that are many orders of magnitude larger than spaces that can be treated by conventional diagonalization methods and has proven to be a powerful tool in the microscopic calculation of level densities. We discuss recent applications of the method in heavy nuclei.Conference Object Microscopic Nuclear Level Densities by the Shell Model Monte Carlo Method(Cern, 2015) Alhassid, Yoram; Bertsch, George F.; Gilbreth, Christopher N.; Nakada, Hitoshi; Özen, CemThe 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 in mid-mass and heavy nuclei. The shell model Monte Carlo (SMMC) method permits calculations in model spaces that are many orders of magnitude larger than spaces that can be treated by conventional diagonalization methods. We discuss recent progress in the SMMC approach to level densities and in particular the calculation of level densities in heavy nuclei. We calculate the distribution of the axial quadrupole operator in the laboratory frame at finite temperature and demonstrate that it is a model-independent signature of deformation in the rotational invariant framework of the shell model. We propose a method to use these distributions for calculating level densities as a function of intrinsic deformation. © 2015 CERN. All rights reserved.Book Part Citation - Scopus: 0Microsopic Nuclear Level Densities by the Shell Model Monte Carlo Method(CERN, 2015) Alhassid, Yoram; Bertsch, George F.; Gilberth, Nichole C.; Nakada, Hitoshi; Özen, CemThe 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 in mid-mass and heavy nuclei. The shell model Monte Carlo (SMMC) method permits calculations in model spaces that are many orders of magnitude larger than spaces that can be treated by conventional diagonalization methods. We discuss recent progress in the SMMC approach to level densities, and in particular the calculation of level densities in heavy nuclei. We calculate the distribution of the axial quadrupole operator in the laboratory frame at finite temperature and demonstrate that it is a model-independent signature of deformation in the rotational invariant framework of the shell model. We propose a method to use these distributions for calculating level densities as a function of intrinsic deformation.
