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We present a new method for computing the lowest few eigenvalues and the corresponding eigenvectors of a nuclear many-body Hamiltonian represented in a truncated configuration interaction subspace, i.e., the no-core shell model (NCSM). The…

Computational Physics · Physics 2024-07-16 Dong Min Roh , Esmond Ng , Chao Yang , Dean Lee , Pieter Maris , James P. Vary

The shell model Monte Carlo (SMMC) method is a powerful technique for calculating the statistical and collective properties of nuclei in the presence of correlations in model spaces that are many orders of magnitude larger than those that…

Nuclear Theory · Physics 2015-06-23 Y. Alhassid , M. Bonett-Matiz , A. Mukherjee , H. Nakada , C. Özen

Jacobian-vector products (JVPs) form the backbone of many recent developments in Deep Networks (DNs), with applications including faster constrained optimization, regularization with generalization guarantees, and adversarial example…

Machine Learning · Computer Science 2021-04-02 Randall Balestriero , Richard Baraniuk

In this study, the artificial neural network method has been employed for the generation of the new two-body matrix elements which is used for pfg shell nuclei. For this purpose, jj44b interaction Hamiltonian has been considered as a…

Nuclear Theory · Physics 2019-07-09 Serkan Akkoyun

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

Inspired by the latest developments in multilevel Monte Carlo (MLMC) methods and randomised sketching for linear algebra problems we propose a MLMC estimator for real-time processing of matrix structured random data. Our algorithm is…

Numerical Analysis · Mathematics 2020-04-30 Yue Wu , Nick Polydorides

Computational Fluid Dynamics (CFD) simulations are often constrained by the memory-bound nature of sparse matrix-vector operations, which eventually limits performance on modern high-performance computing (HPC) systems. This work introduces…

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 introduce the pCI software package for high-precision atomic structure calculations. The standard method of calculation is based on the configuration interaction (CI) method to describe valence correlations, but can be extended to attain…

In calculating integral or discrete transforms, use has been made of fast algorithms for multiplying vectors by matrices whose elements are specified as values of special (Chebyshev, Legendre, Laguerre, etc.) functions. The currently…

Numerical Analysis · Mathematics 2022-08-11 Andrew V. Terekhov

The nucleon pair shell model (NPSM) is casted into the so-called M-scheme for the cases with isospin symmetry and without isospin symmetry. The odd system and even system are treated on the same foot. The uncoupled commutators for…

Nuclear Theory · Physics 2020-08-12 BingCheng He , Yu Zhang , Lei Li , YanAn Luo , Feng Pan , J. P. Draayer

Modern applications of atomic physics, including the determination of frequency standards, and the analysis of astrophysical spectra, require prediction of atomic properties with exquisite accuracy. For complex atomic systems,…

Atomic Physics · Physics 2024-08-02 Pavlo Bilous , Charles Cheung , Marianna Safronova

Conventional diagonalization methods to calculate nuclear energy levels in the framework of the configuration-interaction (CI) shell model approach are prohibited in very large model spaces. The shell model Monte Carlo (SMMC) is a powerful…

Nuclear Theory · Physics 2025-01-08 Y. Alhassid , M. Bonett-Matiz , C. N. Gilbreth , S. Vartak

We consider a fast, data-sparse directional method to realize matrix-vector products related to point evaluations of the Helmholtz kernel. The method is based on a hierarchical partitioning of the point sets and the matrix. The considered…

Numerical Analysis · Mathematics 2021-01-08 Günther Of , Raphael Watschinger

We present an efficient numerical method for computing Hamiltonian matrix elements between non-orthogonal Slater determinants, focusing on the most time-consuming component of the calculation that involves a sparse array. In the usual case…

Nuclear Theory · Physics 2012-10-22 Yutaka Utsuno , Noritaka Shimizu , Takaharu Otsuka , Takashi Abe

The Shell Model Monte Carlo (SMMC) approach has been applied to calculate level densities and partition functions to temperatures up to ~ 1.5 - 2 MeV, with the maximal temperature limited by the size of the configuration space. Here we…

Nuclear Theory · Physics 2009-11-10 Y. Alhassid , G. F. Bertsch , L. Fang

Recent studies have demonstrated improved skill in numerical weather prediction via the use of spatially correlated observation error covariance information in data assimilation systems. In this case, the observation weighting matrices…

Numerical Analysis · Mathematics 2022-01-05 Guannan Hu , Sarah L. Dance

We study the approximation of integrals $\int_D f(\boldsymbol{x}^\top A) \mathrm{d} \mu(\boldsymbol{x})$, where $A$ is a matrix, by quasi-Monte Carlo (QMC) rules $N^{-1} \sum_{k=0}^{N-1} f(\boldsymbol{x}_k^\top A)$. We are interested in…

Numerical Analysis · Mathematics 2023-05-22 Josef Dick , Adrian Ebert , Lukas Herrmann , Peter Kritzer , Marcello Longo

The matrix element technique provides a superior statistical sensitivity for precision measurements of important parameters at hadron colliders, such as the mass of the top quark or the cross section for the production of Higgs bosons. The…

High Energy Physics - Experiment · Physics 2014-11-20 Oleg Brandt , Gaston Gutierrez , Michael H. L. S. Wang , Zhenyu Ye

The shell model Monte Carlo (SMMC) approach allows for the microscopic calculation of statistical and collective properties of heavy nuclei using the framework of the configuration-interaction shell model in very large model spaces. We…

Nuclear Theory · Physics 2015-06-23 C. Özen , Y. Alhassid , H. Nakada
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