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[Background:] It is well known that effective nuclear interactions are in general nonlocal. Thus if nuclear densities obtained from {\it ab initio} no-core-shell-model (NCSM) calculations are to be used in reaction calculations,…

Nuclear Theory · Physics 2018-02-28 M. Burrows , Ch. Elster , G. Popa , K. D. Launey , A. Nogga , P. Maris

The SS-HORSE-NCSM method is generalized to the case of democratic decay into an odd number of fragments. This method is applied to the search for resonances in three-neutron system (trineutron) using ab initio No-Core Shell Model…

Nuclear Theory · Physics 2024-08-22 I. A. Mazur , M. K. Efimenko , A. I. Mazur , I. J. Shin , V. A. Kulikov , A. M. Shirokov , J. P. Vary

We discuss the role of clustering on monopole, dipole, and quadrupole excitations in nuclei in the framework of the ab initio symmetry-adapted no-core shell model (SA-NCSM). The SA-NCSM starts from nucleon-nucleon potentials and, by…

Nuclear Theory · Physics 2018-12-20 R. B. Baker , K. D. Launey , N. Nevo Dinur , S. Bacca , J. P. Draayer , T. Dytrych

Using the recently developed exact numerical renormalization group (NRG) method, we analyse the NRG truncation errors $\delta \chi$ of the local magnetic susceptibility and $\delta F$ of the free energy for the spin-boson model (SBM). We…

Strongly Correlated Electrons · Physics 2020-10-12 Ke Yang , Ning-Hua Tong

Selected configuration interaction (SCI) methods have emerged as state-of-the-art methodologies for achieving high accuracy and generating benchmark reference data for ground and excited states in small molecular systems. However, their…

Chemical Physics · Physics 2024-06-13 Hugh G. A. Burton , Pierre-François Loos

We extend the ab initio no-core shell model/resonating-group method (NCSM/RGM) to projectile-target binary-cluster states where the projectile is a deuteron. We discuss the formalism in detail and give algebraic expressions for the…

Nuclear Theory · Physics 2015-03-18 Petr Navratil , Sofia Quaglioni

Propagation of uncertainties from two-nucleon potential parameters to three-nucleon observables, that is statistical errors for the neutron-deuteron elastic scattering and the deuteron breakup reaction at neutron laboratory energies up to…

Nuclear Theory · Physics 2020-03-16 Yu. Volkotrub , J. Golak , R. Skibiński , K. Topolnicki , H. Witała , E. Epelbaum , H. Krebs , P. Reinert

The nuclear structure dependence of direct reactions that remove a pair of like or unlike nucleons from a fast $^{12}$C projectile beam are considered. Specifically, we study the differences in the two-nucleon correlations present and the…

Nuclear Theory · Physics 2015-06-05 E. C. Simpson , P. Navrátil , R. Roth , J. A. Tostevin

Large-space no-core shell model calculations have been performed for A=3-6 nuclei, using a starting-energy-independent two-body effective interaction derived by application of the Lee-Suzuki similarity transformation. This transformation…

Nuclear Theory · Physics 2008-11-26 P. Navratil , B. R. Barrett

We evaluate the coincidence spectra in the nonmesonic weak decay (NMWD) $\Lambda N\go nN$ of $\Lambda$ hypernuclei $^{4}_\Lambda$He, $^{5}_\Lambda$He, $^{12}_\Lambda$C, $^{16}_\Lambda$O, and $^{28}_\Lambda$Si, as a function of the sum of…

Nuclear Theory · Physics 2008-11-26 Cesar Barbero , Alfredo P. Galeao , Mahir S. Hussein , Francisco Krmpotic

We present a family of nucleon-nucleon (NN) plus three-nucleon (3N) interactions up to N3LO in the chiral expansion that provides an accurate ab initio description of ground-state energies and charge radii up to the medium-mass regime with…

Nuclear Theory · Physics 2020-08-26 Thomas Hüther , Klaus Vobig , Kai Hebeler , Ruprecht Machleidt , Robert Roth

We present a method to extrapolate nuclear binding energies from known values for neighbouring nuclei. We select four specific mass relations constructed to eliminate smooth variation of the binding energy as function nucleon numbers. The…

Nuclear Theory · Physics 2014-08-27 D. Hove , A. S. Jensen , K. Riisager

A symplectic no-core shell model (Sp-NCSM) is constructed with the goal of extending the {\it ab-initio} NCSM to include strongly deformed higher-oscillator-shell configurations and to reach heavier nuclei that cannot be studied currently…

The energy variance extrapolation method consists in relating the approximate energies in many-body calculations to the corresponding energy variances and inferring eigenvalues by extrapolating to zero variance. The method needs a fast…

Nuclear Theory · Physics 2015-06-03 G. Puddu

The in-medium similarity renormalization group (IMSRG) is a powerful and flexible many-body method to compute the structure of nuclei starting from nuclear forces. Recent developments have extended the IMSRG from its standard truncation at…

Nuclear Theory · Physics 2025-03-12 M. Heinz , T. Miyagi , S. R. Stroberg , A. Tichai , K. Hebeler , A. Schwenk

The triaxial projected shell model (TPSM) approach is generalized to investigate the negative parity band structures in even-even systems. In the earlier version of the TPSM approach, the quasiparticle excitations were restricted to one…

Nuclear Theory · Physics 2023-09-06 Nazira Nazir , S. Jehangir , S. P. Rouoof , G. H. Bhat , J. A. Sheikh , N. Rather , Manzoor A. Malik

We report on the computational characteristics of ab initio nuclear structure calculations in a symmetry-adapted no-core shell model (SA-NCSM) framework. We examine the computational complexity of the current implementation of the SA-NCSM…

Projection Monte Carlo calculations of lattice Chiral Effective Field Theory suffer from sign oscillations to a varying degree dependent on the number of protons and neutrons. Hence, such studies have hitherto been concentrated on nuclei…

Large-scale shell-model calculations are carried out in the model space including neutron-hole orbitals $2p_{1/2}$, $1f_{5/2}$, $2p_{3/2}$, $0i_{13/2}$, $1f_{7/2}$ and $0h_{9/2}$ to study the structure and electromagnetic properties of…

Nuclear Theory · Physics 2016-07-20 Chong Qi , L. Y. Jia , G. J. Fu

The non-perturbative {\it ab initio} calculations of infinite nuclear matter using In-Medium Similarity Renormalization Group (IMSRG) method is developed in this work, which enables calculations with chiral two and three-nucleon forces at…

Nuclear Theory · Physics 2025-02-27 Xin Zhen , Rongzhe Hu , Haoyu Shang , Jiawei Chen , Junchen Pei , Furong Xu