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Nuclear physics experiments give reaction rates that, via modelling and comparison with primordial abundances, constrain cosmological parameters. The error bars of a key reaction, \dpg, were tightened in 2020, bringing to light…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-23 Cyril Pitrou , Alain Coc , Jean-Philippe Uzan , Elisabeth Vangioni

We present the continued fraction method (CFM) as a new microscopic approximation to the spectral density of the Hubbard model in the correlated metal phase away from half filling. The quantity expanded as a continued fraction is the single…

Strongly Correlated Electrons · Physics 2009-11-11 R. Hayn , P. Lombardo , K. Matho

We consider the approximation in the reaction-diffusion norm with continuous finite elements and prove that the best error is equivalent to a sum of the local best errors on pairs of elements. The equivalence constants do not depend on the…

Numerical Analysis · Mathematics 2018-03-07 Francesca Tantardini , Andreas Veeser , R"udiger Verf"urth

The tensor optimized Fermi sphere (TOFS) method is applied first for the study of the property of nuclear matter using the Argonne V4' $NN$ potential. In the TOFS method, the correlated nuclear matter wave function is taken to be a…

Nuclear Theory · Physics 2018-08-27 Taiichi Yamada , Takayuki Myo , Hisashi Horiuchi , Kiyomi Ikeda , Hiroshi Toki

The Rosen fractions are an infinite set of continued fraction algorithms, each giving expansions of real numbers in terms of certain algebraic integers. For each, we give a best possible upper bound for the minimum in appropriate…

Number Theory · Mathematics 2007-08-27 Cor Kraaikamp , Thomas A. Schmidt , Ionica Smeets

We generalize the problem of strongly interacting neutron matter by adding a periodic external modulation. This allows us to study from first principles a neutron system that is extended and inhomogeneous, with connections to the physics of…

Nuclear Theory · Physics 2016-04-13 Mateusz Buraczynski , Alexandros Gezerlis

The optimized random phase approximation (ORPA) for classical liquids is re-examined in the framework of the generating functional approach to the integral equations. We show that the two main variants of the approximation correspond to the…

Chemical Physics · Physics 2009-10-30 G. Pastore , O. Akinlade , F. Matthews , Z. Badirkhan

The Random Phase Approximation (RPA) and its variations and extensions are, without any doubt, the most widely used tools to describe Giant Resonances within a microscopic theory. In this chapter, we will start by discussing how RPA comes…

Nuclear Theory · Physics 2022-01-13 Gianluca Colo'

It is shown that the random-phase approximation (RPA) method with its nonlinear generalization, which was previously considered as approximation, reproduces the exact solutions of the Lipkin model. The nonlinear RPA is based on an equation…

Nuclear Theory · Physics 2017-11-22 J. Terasaki , A. Smetana , F. Šimkovic , M. I. Krivoruchenko

Response functions in nuclear matter at finite temperature are considered beyond the usual Hartree-Fock (HF) plus Random Phase Approximation (RPA) scheme. The contributions due to the propagator for the dressed nucleons and the…

Nuclear Theory · Physics 2009-11-10 P. Bozek , J. Margueron , H. Muther

Range-separated methods combining a short-range density functional with long-range random phase approximations RPAs with or without exchange response kernel are tested on rare-gas dimers and the S22 benchmark set of weakly interacting…

Chemical Physics · Physics 2014-04-10 Wuming Zhu , Julien Toulouse , Andreas Savin , János G. Angyán

The iterative quasi-particle-random-phase approximation (QRPA) method we previously developed to accurately calculate properties of individual nuclear states is extended so that it can be applied for nuclei with odd numbers of neutrons and…

Nuclear Theory · Physics 2014-06-03 B. G. Carlsson , J. Toivanen

Random Phase Approximation (RPA) is the theory most commonly used to describe the excitations of many-body systems. In this article, the secular equations of the theory are obtained by using three different approaches: the equation of…

Nuclear Theory · Physics 2023-03-14 Giampaolo Co'

Developing theoretical understanding of complex reactions and processes at interfaces requires using methods that go beyond semilocal density functional theory to accurately describe the interactions between solvent, reactants and…

We assess the performance of a recently proposed renormalized adiabatic local density approximation (rALDA) for \textit{ab initio} calculations of electronic correlation energies in solids and molecules. The method is an extension of the…

Materials Science · Physics 2014-05-30 Thomas Olsen , Kristian S. Thygesen

The goal of this paper is to formulate a systematical method for constructing the fastest possible continued fraction approximations of a class of functions. The main tools are the multiple-correction method, the generalized Mortici's lemma…

Classical Analysis and ODEs · Mathematics 2015-08-04 Xiaodong Cao , Yoshio Tanigawa , Wenguang Zhai

We describe an approximate rational arithmetic with round-off errors (both absolute and relative) controlled by the user. The rounding procedure is based on the continued fraction expansion of real numbers. Results of computer experiments…

Numerical Analysis · Mathematics 2025-10-20 Grigori Litvinov , Anatoli Rodionov , Andrei Chourkin

Reliable predictions of nuclear properties are needed as much to answer fundamental science questions as in applications such as reactor physics or data evaluation. Nuclear density functional theory is currently the only microscopic, global…

Nuclear Theory · Physics 2015-01-23 N. Schunck , J. D. McDonnell , D. Higdon , J. Sarich , S. Wild

The random phase approximation (RPA) for the electron correlation energy, combined with the exact-exchange energy, represents the state-of-the-art exchange-correlation functional within density-functional theory (DFT). However, the standard…

Other Condensed Matter · Physics 2015-05-20 Xinguo Ren , Patrick Rinke , Alexandre Tkatchenko , Matthias Scheffler

The fully consistent relativistic proton-neutron quasiparticle random phase approximation (PN-RQRPA) is employed in the calculation of beta-decay half-lives of neutron-rich nuclei in the N$\approx$50 and N$\approx$82 regions. A new…

Nuclear Theory · Physics 2009-02-18 T. Niksic , T. Marketin , D. Vretenar , N. Paar , P. Ring