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Several approximations are tested by calculating the ground-state energy and the energy of the first excited $0^{+}$ state using an exactly solvable model with two symmetric levels interacting via a pairing force. They are the BCS…

Nuclear Theory · Physics 2009-09-29 Nguyen Dinh Dang

An exactly solvable model is introduced, which is equivalent to the exact shell-model treatment of protons and neutrons in a single j-shell for Fermi-type excitations. Exact energies, quasiparticle numbers and double beta decay Fermi…

Nuclear Theory · Physics 2007-05-23 Jorge G. Hirsch , Peter O. Hess , Osvaldo Civitarese

We discuss properties of the quadrupole collective excitation of the deformed neutron-rich nucleus $^{38}$Mg within the framework of quasi-particle random phase approximation (QRPA). We first solve the coupled-channels equations to obtain…

Nuclear Theory · Physics 2015-06-26 K. Hagino , Nguyen Van Giai , H. Sagawa

It is demonstrated that non-constant kernel solution, that can fit the spatial variations of the kernel can be obtained with minimum computing time. The CPU cost required with this new extension of the image subtraction method is almost the…

Astrophysics · Physics 2007-05-23 C. Alard

We construct range-separated double-hybrid schemes which combine coupled-cluster or random-phase approximations with a density functional based on a two-parameter Coulomb-attenuating-method-like decomposition of the electron-electron…

Chemical Physics · Physics 2020-01-29 Cairedine Kalai , Bastien Mussard , Julien Toulouse

Sparse Principal Component Analysis (SPCA) is a fundamental technique for dimensionality reduction, and is NP-hard. In this paper, we introduce a randomized approximation algorithm for SPCA, which is based on the basic SDP relaxation. Our…

Machine Learning · Statistics 2026-05-19 Alberto Del Pia , Dekun Zhou

The first, to our knowledge, calculation of neutrinoless double beta decay ($0\nu\beta\beta$-decay) matrix elements within the self-consistent renormalised Quasiparticle Random Phase Approximation (SRQRPA) is presented. The contribution…

Nuclear Theory · Physics 2009-02-18 A. Bobyk , W. A. Kaminski , F. Simkovic

Theoretical studies of low-lying dipole strength in even-even spherical nuclei within the relativistic quasiparticle time blocking approximation (RQTBA) are presented. The RQTBA developed recently as an extension of the self-consistent…

Nuclear Theory · Physics 2009-08-03 E. Litvinova , P. Ring , V. Tselyaev , K. Langanke

We proposed a novel dense line spectrum super-resolution algorithm, the DMRA, that leverages dynamical multi-resolution of atoms technique to address the limitation of traditional compressed sensing methods when handling dense point-source…

Signal Processing · Electrical Eng. & Systems 2024-09-04 Mingguang Han , Yi Zeng , Xiaoguang Li , Tiejun Li

The properties of the low-energy dipole response are investigated for the proton-rich doubly magic nucleus $^{48}$Ni, in a comparative study of two microscopic models: fully self-consistent Relativistic Random-Phase Approximation(RRPA)…

Nuclear Theory · Physics 2009-11-11 N. Paar , P. Papakonstantinou , V. Yu. Ponomarev , J. Wambach

We show how the longstanding problem of the collapse of the charge-exchange QRPA near the physical value of the force strength can be circumvented. This is done by including the effect of ground state correlations into the QRPA equations of…

Nuclear Theory · Physics 2007-05-23 F. Krmpotic , A. Mariano , T. T. S. Kuo , E. J. V. de Passos , A. F. R. de Toledo Piza

The $2\nu\beta\beta$-decay nuclear matrix elements (NMEs) for 11 nuclei are studied with the self-consistent quasiparticle random phase approximation (QRPA) based on Skyrme Hartree-Fock-Bogoliubov (Skyrme HFB) model. As a common feature…

Nuclear Theory · Physics 2022-04-27 W. L. Lv , Y. F. Niu , D. L. Fang , C. L. Bai

The relativistic proton-neutron quasiparticle random phase approximation (PN-RQRPA) is applied in the calculation of beta-decay half-lives of neutron-rich nuclei in the $Z\approx 28$ and $Z\approx 50$ regions. The study is based on the…

Nuclear Theory · Physics 2008-11-26 T. Marketin , D. Vretenar , P. Ring

A microscopic model aimed at the description of charge-exchange nuclear excitations along isotopic chains which include open-shell systems, is developed. It consists of quasiparticle random phase approximation (QRPA) made on top of…

Nuclear Theory · Physics 2009-02-18 S. Fracasso , G. Colo`

The neutron and proton scattering with either deuteron or stable alpha particle can be modeled as a two particle system. In this paper, using Morse function as reference potential, inverse potentials have been computationally constructed…

Nuclear Theory · Physics 2022-09-27 Lalit Kumar , Shikha Awasthi , Anil Khachi , O. S. K. S Sastri

The hole-state random phase approximation (hRPA) and the particle-state random phase approximation (pRPA) for systems like odd $A$ nuclei are discussed. These hRPA and pRPA are formulated based on the Hartree-Fock ground state. An extension…

Nuclear Theory · Physics 2015-06-12 Mitsuru Tohyama , Peter Schuck

Solving the many-electron problem, even approximately, is one of the most challenging and simultaneously most important problems in contemporary condensed matter physics with various connections to other fields. The standard approach is to…

Strongly Correlated Electrons · Physics 2026-04-10 Jonas B. Profe , Jakša Vučičević , P. Peter Stavropoulos , Malte Rösner , Roser Valentí , Lennart Klebl

In the past decades, the \gamma-decay of giant resonances has been studied using phenomenological models. In keeping with possible future studies performed with exotic beams, microscopically-based frameworks should be envisaged. In the…

Nuclear Theory · Physics 2015-06-03 Marco Brenna , Gianluca Colò , Pier Francesco Bortignon

The projected random phase approximation (PRPA) for charge-exchange excitations is derived from the time-dependent variational principle. Explicit results for the unperturbed energies (including the self-energy corrections), the PRPA…

Nuclear Theory · Physics 2016-08-14 F. Krmpotić , A. Mariano , T. T. S. Kuo , K. Nakayama

The two-stage stochastic unit commitment problem has become an important tool to support decision-making under uncertainty in power systems. Representing the uncertainty by a large number of scenarios guarantees accurate results but…

Optimization and Control · Mathematics 2025-12-23 Yannick Werner , Juan Miguel Morales , Salvador Pineda , Line Roald , Sonja Wogrin