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Background: Ab initio many-body methods whose numerical cost scales polynomially with the number of particles have been developed over the past fifteen years to tackle closed-shell mid-mass nuclei. Open-shell nuclei have been further…

Nuclear Theory · Physics 2018-06-27 Julien Ripoche , Thomas Duguet , Jean-Paul Ebran , Denis Lacroix

We study analytically and experimentally certain symplectic and time-reversible N-body integrators which employ a Kepler solver for each pair-wise interaction, including the method of Hernandez & Bertschinger (2015). Owing to the Kepler…

Numerical Analysis · Mathematics 2017-03-03 Walter Dehnen , David M. Hernandez

We present an overview of recent results and developments of the no-core shell model (NCSM), an ab initio approach to the nuclear many-body problem for light nuclei. In this approach, we start from realistic two-nucleon or two- plus…

Nuclear Theory · Physics 2009-06-19 Petr Navratil , Sofia Quaglioni , Ionel Stetcu , Bruce R. Barrett

We present a novel scheme for nuclear structure calculations based on realistic nucleon-nucleon potentials. The essential ingredient is the explicit treatment of the dominant interaction-induced correlations by means of the Unitary…

Nuclear Theory · Physics 2009-11-10 R. Roth , T. Neff , H. Hergert , H. Feldmeier

A simple two-level model is developed and used to test the properties of effective interactions for performing nuclear structure calculations in truncated model spaces. It is shown that the effective many-body interactions sensitively…

Nuclear Theory · Physics 2009-10-22 B. R. Barrett , D. C. Zheng , R. J. McCarthy , J. P. Vary

We present a method to calculate many-body states of interacting carriers in million atom quantum nanostructures based on atomistic tight-binding calculations and a combination of iterative selection of configurations and perturbation…

Mesoscale and Nanoscale Physics · Physics 2020-05-27 Moritz Cygorek , Matthew Otten , Marek Korkusinski , Pawel Hawrylak

The no-core shell model (NCSM) is an \textit{ab initio} method that solves the nuclear many-body problem by expanding the many-particle wave function into a (typically) harmonic oscillator basis and minimizing the energy to obtain the…

Nuclear Theory · Physics 2024-02-06 Konstantinos Kravvaris , Sofia Quaglioni , Petr Navratil

Exact symmetry and symmetry-breaking phenomena play a key role in gaining a better understanding of the physics of many-particle systems, from quarks and atomic nuclei, through molecules and galaxies. In nuclei, exact and dominant…

The Similarity Renormalization Group (SRG) is used to soften interactions for ab initio nuclear structure calculations by decoupling low- and high-energy Hamiltonian matrix elements. The substantial contribution of both initial and…

Nuclear Theory · Physics 2013-05-22 E. D. Jurgenson , P. Maris , R. J. Furnstahl , P. Navratil , W. E. Ormand , J. P. Vary

The similarity renormalization group (SRG) has been successfully applied to soften interactions for ab initio nuclear calculations. In almost all practical applications in nuclear physics, an SRG generator with the kinetic energy operator…

Nuclear Theory · Physics 2014-09-10 Nuiok M. Dicaire , Conor Omand , Petr Navratil

Semi-leptonic electroweak interactions in nuclei - such as \beta decay, \mu capture, charged- and neutral-current neutrino reactions, and electron scattering - are described by a set of multipole operators carrying definite parity and…

Nuclear Theory · Physics 2009-11-13 Wick Haxton , Cecilia Lunardini

We review the ab initio symmetry-adapted (SA) framework for determining the structure of stable and unstable nuclei, along with related electroweak, decay and reaction processes. This framework utilizes the dominant symmetry of nuclear…

Nuclear Theory · Physics 2021-08-12 Kristina D. Launey , Alexis Mercenne , Tomas Dytrych

This paper addresses the challenges of solving the quantum many-body problem, particularly within nuclear physics, through the configuration interaction (CI) method. Large-scale shell model calculations often become computationally…

Nuclear Theory · Physics 2025-07-17 Priyanka Choudhary , Chong Qi

We present a variational Monte Carlo method that solves the nuclear many-body problem in the occupation number formalism exploiting an artificial neural network representation of the ground-state wave function. A memory-efficient version of…

We present a microscopic description of nuclei in an intermediate-mass region, including the proximity to the proton drip line, based on a no-core shell model with a schematic many-nucleon long-range interaction with no parameter…

Nuclear Theory · Physics 2015-06-17 G. K. Tobin , M. C. Ferriss , K. D. Launey , T. Dytrych , J. P. Draayer , A. C. Dreyfuss , C. Bahri

Recently it was argued that it might be possible treat the conventional nuclear structure problem -- nonrelativistic point nucleons interacting through a static and rather singular potential -- as an effective theory in a shell-model basis.…

Nuclear Theory · Physics 2009-11-07 W. C. Haxton , T. Luu

We present a unifying theoretical framework that describes recently observed many-body effects during the interrogation of an optical lattice clock operated with thousands of fermionic alkaline earth atoms. The framework is based on a…

We benchmark three standard approximations for the many-body problem -- the Hartree-Fock, projected Hartree-Fock, and random phase approximations -- against full numerical configuration-interaction calculations of the electronic structure…

Atomic Physics · Physics 2012-08-31 Micah D. Schuster , Calvin W. Johnson , Joshua T. Staker

We present a scalable framework for accurately modeling many-body interactions in surface-code quantum processor units (QPUs). Combining a concise diagrammatic formalism with high-precision numerical methods, our approach efficiently…

Quantum Physics · Physics 2025-07-09 Xuexin Xu , Kuljeet Kaur , Chloé Vignes , Mohammad H. Ansari , John M. Martinis

Calculations in the ab initio no-core shell model (NCSM) have conventionally been carried out using the harmonic-oscillator many-body basis. However, the rapid falloff (Gaussian asymptotics) of the oscillator functions at large radius makes…

Nuclear Theory · Physics 2014-09-02 M. A. Caprio , P. Maris , J. P. Vary