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Microscopic Combinatorial approach is used to calculate the state and level densities with fixed exciton numbers, in some actinide nuclei. Deformed Saxon-Woods shell model was used as a basis from which all posible configurations were…

Nuclear Theory · Physics 2019-08-17 F. Garcia , O Rodriguez , F. Guzman , H. Dias , J. D. T Arruda-Neto , M. S. Hussein , A. K. Kerman

A simple formula for the ratio of the number of odd- and even-parity states as a function of temperature is derived. This formula is used to calculate the ratio of level densities of opposite parities as a function of excitation energy. We…

Nuclear Theory · Physics 2009-10-31 Y. Alhassid , G. F. Bertsch , S. Liu , H. Nakada

We systematically study the nuclear level densities of superheavy nuclei, including odd systems, using the single-particle energies obtained with the Woods-Saxon potential diagonalization. Minimization over many deformation parameters for…

A fully microscopic model for the description of nuclear level density (NLD) in spherical nuclei is proposed. The model is derived by combining the partition function of the exact pairing solution plus the independent-particle model at…

Nuclear Theory · Physics 2020-12-02 N. Quang Hung , N. Dinh Dang , L. Tan Phuc , N. Ngoc Anh , T. Dong Xuan , T. V. Nhan Hao

We introduce spin projection methods in the shell model Monte Carlo approach and apply them to calculate the spin distribution of level densities for iron-region nuclei using the complete $(pf+g_{9/2})$-shell. We compare the calculated…

Nuclear Theory · Physics 2008-11-26 Y. Alhassid , S. Liu , H. Nakada

Recently we proposed a formalism, based in nuclear statistical spectroscopy, for efficient computation of nuclear level density, or densities of states, through a sum of partitioned binomial functions (SUPARB). In this Letter we extend the…

Nuclear Theory · Physics 2007-05-23 Calvin W. Johnson , Jameel-Un Nabi , W. Erich Ormand

The Projected Shell Model with zero-, two- and four-quasiparticle configurations is used to investigate the level statistics, i.e. chaoticity, of high spin spectroscopy. The model can describe many high spin phenomena and with the present…

Nuclear Theory · Physics 2009-09-25 Yang Sun , Da Hsuan Feng , Hsi-Tseng Chen , Hua Wu

A simple description for obtaining the parity distribution of nuclear levels in the pf + g9/2 shell as a function of excitation energy was recently derived. We implement this in a global nuclear level density model. In the framework of the…

Nuclear Theory · Physics 2015-06-26 D. Mocelj , T. Rauscher , G. Martinez-Pinedo , Y. Alhassid

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

Nuclear level densities are crucial for estimating statistical nuclear reaction rates. The shell model Monte Carlo method is a powerful approach for microscopic calculation of state densities in very large model spaces. However, these state…

Nuclear Theory · Physics 2013-04-29 Y. Alhassid , M. Bonett-Matiz , S. Liu , H. Nakada

Numerical resolution of high-dimensional nonlinear PDEs remains a huge challenge due to the curse of dimensionality. Starting from the weak formulation of the Lawson-Euler scheme, this paper proposes a stochastic particle method (SPM) by…

Numerical Analysis · Mathematics 2025-02-11 Zhengyang Lei , Sihong Shao , Yunfeng Xiong

We review recent advances in the shell model Monte Carlo approach for the microscopic calculation of statistical and collective properties of nuclei. We discuss applications to the calculation of (i) level densities in nickel isotopes,…

Nuclear Theory · Physics 2016-01-05 Y. Alhassid

Levels densities of independent-particle Hamiltonians can be calculated easily by using the real-time representation of the evolution operator together with the fast Fourier transform. We describe the method and implement it with a set of…

Nuclear Theory · Physics 2015-06-18 G. F. Bertsch , L. M. Robledo

The seniority scheme has been shown to be extremely useful for the classification of nuclear states in semi-magic nuclei. The neutron-proton ($np$) correlation breaks the seniority symmetry in a major way. As a result, the corresponding…

Nuclear Theory · Physics 2012-10-03 C. Qi , J. Blomqvist , T. Bäck , B. Cederwall , A. Johnson , R. J. Liotta , R. Wyss

It is shown that the Constant Temperature (CT) model of nuclear level density is a direct consequence of a symmetrized Poisson distribution of nuclear level spacings. The standard CT model describing the total level density is shown to be…

Nuclear Theory · Physics 2021-04-07 Richard B. Firestone

Performing a shell model calculation for heavy nuclei has been a long-standing problem in nuclear physics. Here we propose one possible solution. The central idea of this proposal is to take the advantages of two existing models, the…

Nuclear Theory · Physics 2009-11-10 Yang Sun , Cheng-Li Wu

We present a new combinatorial method for the calculation of the nuclear level density. It is based on a Monte Carlo technique, in order to avoid a direct counting procedure which is generally impracticable for high-A nuclei. The Monte…

Nuclear Theory · Physics 2008-11-26 N. Cerf

Total and parity-projected level densities of iron-region nuclei are calculated microscopically by using Monte Carlo methods for the nuclear shell model in the complete $(pf+0g_{9/2})$-shell. The calculated total level density is found to…

Nuclear Theory · Physics 2007-05-23 H. Nakada , Y. Alhassid

Measurements of nuclear spin-dependent parity-violating (NSD-PV) effects provide an excellent opportunity to test nuclear models and to search for physics beyond the Standard Model. Molecules possess closely-spaced states with opposite…

In this paper, Kernel Density Estimation (KDE) as a non-parametric estimation method is used to investigate statistical properties of nuclear spectra. The deviation to regular or chaotic dynamics, is exhibited by closer distances to Poisson…

Nuclear Theory · Physics 2011-12-13 M. A. Jafarizadeh , N. Fouladi , H. Sabri , B. Rashidian Maleki