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We developed an implicit Particle-in-cell/Monte Carlo model in two-dimensional and axisymmetric geometry for the simulations of the radio-frequency discharges, by introducing several numerical schemes which include variable weights,…

Plasma Physics · Physics 2011-04-19 Hong-yu Wang , Wei Jiang , You-nian Wang

We give exact formulae for a wide family of complexity measures that capture the organization of hidden nonlinear processes. The spectral decomposition of operator-valued functions leads to closed-form expressions involving the full…

Statistical Mechanics · Physics 2013-09-17 James P. Crutchfield , Christopher J. Ellison , Paul M. Riechers

A high-performance Fortran code is developed to calculate the spin- and parity-dependent shell model nuclear level densities.The algorithm is based on the extension of methods of statistical spectroscopy and implies exact calculation of the…

Nuclear Theory · Physics 2015-06-05 R. Sen'kov , M. Horoi , V. G. Zelevinsky

The positive and not completely positive maps of density matrices, which are contractive maps, are discussed as elements of a semigroup. A new kind of positive map (the purification map), which is nonlinear map, is introduced. The density…

Quantum Physics · Physics 2007-05-25 V. I. Man'ko , G. Marmo , E. C. G. Sudarshan , F. Zaccaria

One of the fundamental problems in machine learning is the estimation of a probability distribution from data. Many techniques have been proposed to study the structure of data, most often building around the assumption that observations…

Machine Learning · Statistics 2013-02-22 Oren Rippel , Ryan Prescott Adams

For a prototype quadratic Hamiltonian describing a driven, dissipative system, exact matrix elements of the reduced density matrix are obtained from a generating function in terms of the normal characteristic functions. The approach is…

Quantum Physics · Physics 2021-08-24 Sh. Saedi , F. Kheirandish

Shell-model states involving several pseudospin doublets and ``intruder'' levels in nuclei, are combined into larger multiplets. The corresponding single-particle spectrum exhibits a supersymmetric pattern whose origin can be traced to the…

Nuclear Theory · Physics 2017-08-23 A. Leviatan

Analyzing large volumes of high-dimensional data is an issue of fundamental importance in data science, molecular simulations and beyond. Several approaches work on the assumption that the important content of a dataset belongs to a…

Machine Learning · Statistics 2018-03-20 Elena Facco , Maria d'Errico , Alex Rodriguez , Alessandro Laio

This article introduces a general statistical modeling principle called "Density Sharpening" and applies it to the analysis of discrete count data. The underlying foundation is based on a new theory of nonparametric approximation and…

Methodology · Statistics 2021-08-24 Subhadeep Mukhopadhyay

We revisit the classical problem of 3D shape interpolation and propose a novel, physically plausible approach based on Hamiltonian dynamics. While most prior work focuses on synthetic input shapes, our formulation is designed to be…

Computer Vision and Pattern Recognition · Computer Science 2020-04-14 Marvin Eisenberger , Daniel Cremers

Modified Hamiltonians are used in the field of geometric numerical integration to show that symplectic schemes for Hamiltonian systems are accurate over long times. For nonlinear systems the series defining the modified Hamiltonian usually…

Numerical Analysis · Mathematics 2018-11-14 Shami A Alsallami , Jitse Niesen , Frank W Nijhoff

The Hohenberg-Kohn theorem and Kohn-Sham procedure are extended to functionals of the localized intrinsic density of a self-bound system such as a nucleus. After defining the intrinsic-density functional, we modify the usual Kohn-Sham…

Nuclear Theory · Physics 2008-11-26 J. Engel

Density matrix perturbation theory (DMPT) is known as a promising alternative to the Rayleigh-Schr\"odinger perturbation theory, in which the sum-over-state (SOS) is replaced by algorithms with perturbed density matrices as the input…

Chemical Physics · Physics 2020-12-02 Lionel A. Truflandier , Rivo M. Dianzinga , David R. Bowler

The Density Matrix Renormalization Group (DMRG) has become a powerful numerical method that can be applied to low-dimensional strongly correlated fermionic and bosonic systems. It allows for a very precise calculation of static, dynamical…

Condensed Matter · Physics 2007-05-23 Karen Hallberg

Using the seesaw mechanism and a discrete symmetry, we construct a class of models for the neutrino mass matrix where the inverse of that matrix is the sum of a mu-tau antisymmetric background and a perturbation. We consider various…

High Energy Physics - Phenomenology · Physics 2009-11-11 Walter Grimus , Satoru Kaneko , Luis Lavoura , Hideyuki Sawanaka , Morimitsu Tanimoto

The role of discrete (or point-group) symmetries is discussed in the framework of the Cluster Shell Model which describes the splitting of single-particle levels in the deformed field of cluster potentials. We discuss the classification of…

Nuclear Theory · Physics 2020-12-02 A. H. Santana-Valdés , R. Bijker

Using the properties of the local Boltzmann weights of integrable interaction-round-a-face (IRF or face) models we express local operators in terms of generalized transfer matrices. This allows for the derivation of discrete functional…

Statistical Mechanics · Physics 2021-09-15 Holger Frahm , Daniel Westerfeld

The nuclear shell model is one of the successful models in theoretical understanding of nuclear structure. If a convenient effective interaction can be found between nucleons, various observables such as energies of nuclear states are…

Nuclear Theory · Physics 2020-01-24 Serkan Akkoyun , Nadjet Laouet , Fatima Benrachi

We discuss how semidefinite programming can be used to determine the second-order density matrix directly through a variational optimization. We show how the problem of characterizing a physical or N -representable density matrix leads to…

Computational Physics · Physics 2011-10-27 Brecht Verstichel , Helen van Aggelen , Dimitri Van Neck , Paul W. Ayers , Patrick Bultinck

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