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A second order extrapolation method is presented for shell model calculations, where shell model energies of truncated spaces are well described as a function of energy variance by quadratic curves and exact shell model energies can be…

Nuclear Theory · Physics 2009-11-10 Takahiro Mizusaki , Masatoshi Imada

We propose an extrapolation method utilizing energy variance in the Monte Carlo shell model in order to estimate the energy eigenvalue and observables accurately. We derive a formula for the energy variance with deformed Slater…

An extrapolation method in shell model calculations with deformed basis is presented, which uses a scaling property of energy and energy variance for a series of systematically approximated wave functions to the true one. Such approximated…

Nuclear Theory · Physics 2009-11-10 Takahiro Mizusaki

A method of truncating the large shell model basis is outlined. It relies on the order given by the unperturbed energies of the basis states and on the constancy of their spreading widths. Both quantities can be calculated by a simple…

Nuclear Theory · Physics 2009-09-25 Mihai Horoi , B. Alex Brown , Vladimir Zelevinsky

We present a method of filter diagonalization for shell-model calculations. This method is based on the Sakurai and Sugiura (SS) method, but extended with help of the shifted complex orthogonal conjugate gradient (COCG) method. A salient…

Nuclear Theory · Physics 2010-08-27 Takahiro Mizusaki , Kazunari Kaneko , Michio Honma , Tetsuya Sakurai

We propose a new variational Monte Carlo (VMC) method with an energy variance extrapolation for large-scale shell-model calculations. This variational Monte Carlo is a stochastic optimization method with a projected correlated condensed…

Nuclear Theory · Physics 2012-02-14 Takahiro Mizusaki , Noritaka Shimizu

We propose a thick-restart block Lanczos method, which is an extension of the thick-restart Lanczos method with the block algorithm, as an eigensolver of the large-scale shell-model calculations. This method has two advantages over the…

Nuclear Theory · Physics 2019-10-02 Noritaka Shimizu , Takahiro Mizusaki , Yutaka Utsuno , Yusuke Tsunoda

A new method for computing the density of states in nuclei making use of an extrapolated form of the tri-diagonal matrix obtained from the Lanczos method is presented. It will be shown that the global, average properties of the entire…

Nuclear Theory · Physics 2020-07-29 W. E. Ormand , B. A. Brown

We present a newly enhanced version of the Monte Carlo Shell Model method by incorporating the conjugate gradient method and energy-variance extrapolation. This new method enables us to perform large-scale shell-model calculations that the…

We present a procedure that is helpful to reduce the computational complexity of large-scale shell-model calculations, by preserving as much as possible the role of the rejected degrees of freedom in an effective approach. Our truncation is…

Nuclear Theory · Physics 2016-07-07 L. Coraggio , A. Gargano , N. Itaco

We perform an extrapolative analysis of "fast-growth" free-energy-difference (DF) estimates of a computer-modeled, fully-solvated ethane<->methanol transformation. The results suggest that extrapolation can greatly reduce the systematic…

Chemical Physics · Physics 2007-05-23 Daniel M. Zuckerman , Thomas B. Woolf

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 propose an algorithm for molecular dynamics or Monte Carlo simulations that uses an interpolation procedure to estimate potential energy values from energies and gradients evaluated previously at points of a simplicial mesh. We chose an…

Computational Physics · Physics 2020-01-07 Konstantin Karandashev , Jiri Vanicek

We propose an extrapolation technique that allows accuracy improvement of the discrete dipole approximation computations. The performance of this technique was studied empirically based on extensive simulations for 5 test cases using many…

Optics · Physics 2008-07-29 Maxim A. Yurkin , Valeri P. Maltsev , Alfons G. Hoekstra

A method for solving the shell-model eigenproblem in a severely truncated space, spanned by properly selected correlated states obtained by partitioning the full configuration space, is proposed. The method describes in a practically exact…

Nuclear Theory · Physics 2016-09-08 F. Andreozzi , A. Porrino

The truncated Lanczos method using a variational scheme based on Hilbert space reduction as well as a local basis change is re-examined. The energy is extrapolated as a power law function of the Hamiltonian variance. This systematic…

Strongly Correlated Electrons · Physics 2009-10-31 O. Chiappa , S. Capponi , D. Poilblanc

The feasibility of shell-model calculations is radically extended by the Quantum Monte Carlo Diagonalization method with various essential improvements. The major improvements are made in the sampling for the generation of shell-model basis…

Nuclear Theory · Physics 2008-11-26 Michio Honma , Takahiro Mizusaki , Takaharu Otsuka

We propose a computationally efficient technique for extrapolating seismic waves in an arbitrary isotropic elastic medium. The method is based on factorizing the full elastic wave equation into a product of pseudo-differential operators.…

Geophysics · Physics 2012-06-05 Musa Maharramov

We present two developments which enhance the predictive power of empirical shell-model Hamiltonians for cases in which calibration data are sparse. A recent improvement in the ab initio derivation of effective Hamiltonians leads to a much…

Nuclear Theory · Physics 2025-04-25 J. A. Purcell , B. A. Brown , B. C. He , S. R. Stroberg , W. B. Walters

In this present paper, I propose a derivation of unified interpolation and extrapolation function that predicts new values inside and outside the given range by expanding direct Taylor series on the middle point of given data set.…

Numerical Analysis · Mathematics 2020-02-27 Nijat Shukurov
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