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We compute the electric dipole polarizability of 48Ca with an increased precision by including more correlations than in previous studies. Employing the coupled-cluster method we go beyond singles and doubles excitations and include…

Nuclear Theory · Physics 2018-08-01 Mirko Miorelli , Sonia Bacca , Gaute Hagen , Thomas Papenbrock

We introduce a unitary coupled-cluster (UCC) ansatz termed $k$-UpCCGSD that is based on a family of sparse generalized doubles (D) operators which provides an affordable and systematically improvable unitary coupled-cluster wavefunction…

Quantum Physics · Physics 2019-01-07 Joonho Lee , William J. Huggins , Martin Head-Gordon , K. Birgitta Whaley

In a series of two articles, we propose a comprehensive mathematical framework for Coupled-Cluster-type methods. In this second part, we analyze the nonlinear equations of the single-reference Coupled-Cluster method using topological degree…

Numerical Analysis · Mathematics 2023-03-28 Mihály A. Csirik , Andre Laestadius

A microscopic description of nuclei is important to understand the nuclear shell-model from fundamental principles. This is difficult to achieve for more than the lightest nuclei without an effective approximation scheme. The purpose of…

Nuclear Theory · Physics 2013-08-19 Gustav R. Jansen

Coupled cluster methods are widely regarded as the gold standard of computational quantum chemistry as they are perceived to offer the best compromise between computational cost and a high-accuracy resolution of the ground state eigenvalue…

Numerical Analysis · Mathematics 2025-12-03 Muhammad Hassan , Yvon Maday

We tabulate angularly reduced fourth-order many-body corrections to matrix elements for univalent atoms, derived in [A. Derevianko and E.D. Emmons, Phys. Rev. A 65, 052115 (2002)]. In particular we focused on practically important diagrams…

Atomic Physics · Physics 2007-05-23 Andrei Derevianko

Permutation-based partial-correlation tests guarantee finite-sample Type I error control under any fixed design and exchangeable noise, yet their power can collapse when the permutation-augmented design aligns too closely with the covariate…

Methodology · Statistics 2025-06-04 Tianyi Wang , Guanghui Wang , Zhaojun Wang , Changliang Zou

We demonstrate the accuracy of ground-state energies of the transcorrelated Hamiltonian, employing sophisticated Jastrow factors obtained from variational Monte Carlo, together with the coupled cluster and distinguishable cluster methods at…

Recently developed pair coupled cluster doubles (pCCD) theory successfully reproduces doubly occupied configuration interaction (DOCI) with mean field cost. However, the projective nature of pCCD makes the method non-variational and thus…

Chemical Physics · Physics 2016-08-19 Luning Zhao , Eric Neuscamman

Accurate calculations of electric dipole polarizabilities ($\alpha_d$), quadrupole moments ($\Theta$), and quadrupole polarizabilities ($\alpha_q$) for the clock states of the singly charged calcium (Ca$^+$) and ytterbium (Yb$^+$) ions are…

Atomic Physics · Physics 2025-02-11 YanMei Yu , B. K. Sahoo

The coherent potential approximation, CPA, is a useful tool to treat systems with disorder. Cluster theories have been proposed to go beyond the translation invariant single-site CPA approximation and include some short range correlations.…

Condensed Matter · Physics 2009-10-31 C. I. Ventura , R. A. Barrio , .

Supervised machine learning explainability has developed rapidly in recent years. However, clustering explainability has lagged behind. Here, we demonstrate the first adaptation of model-agnostic explainability methods to explain…

Since the appearance of the classical paper of Lifshitz almost half a century ago, linear stability analysis of cosmological models is textbook knowledge. Until recently, however, little was known about the behavior of higher than linear…

Astrophysics · Physics 2007-05-23 R. Juszkiewicz , F. R. Bouchet

We investigate the accuracies of different coupled cluster levels in a finite model solid, the 14 electron spin-non-polarised uniform electron gas. For densities between $\mathrm{r}_\mathrm{s}$ = 0.5 $\mathrm{a}_\mathrm{0}$ and…

Chemical Physics · Physics 2018-03-28 Verena A. Neufeld , Alex J. W. Thom

We introduce a mean-field and perturbative approach, based on clusters, to describe the ground state of fermionic strongly-correlated systems. In cluster mean-field, the ground state wavefunction is written as a simple tensor product over…

Strongly Correlated Electrons · Physics 2016-04-05 Carlos A. Jiménez-Hoyos , Gustavo E. Scuseria

We consider the problem of center-based clustering in low-dimensional Euclidean spaces under the perturbation stability assumption. An instance is $\alpha$-stable if the underlying optimal clustering continues to remain optimal even when…

Data Structures and Algorithms · Computer Science 2020-10-01 Pankaj K. Agarwal , Hsien-Chih Chang , Kamesh Munagala , Erin Taylor , Emo Welzl

We consider the pertubative consistency of inflationary models with features with effective field theory methods. By estimating the size of one-loop contributions to the three-point function, we find the energy scale where their…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-02 Dario Cannone , Nicola Bartolo , Sabino Matarrese

A new perturbative approach to canonical equation-of-motion coupled-cluster theory is presented using coupled-cluster perturbation theory. A second-order M{\o}ller-Plesset partitioning of the Hamiltonian is used to obtain the well known…

Chemical Physics · Physics 2015-07-09 Jason N. Byrd , Varun Rishi , Ajith Perera , Rodney J. Bartlett

The recently developed method combining the configuration interaction and the coupled-cluster method was demonstrated to provide accurate treatment of correlation corrections in divalent atomic systems [M.S.Safronova, M.G.Kozlov, and…

Atomic Physics · Physics 2013-06-12 S. G. Porsev , M. S. Safronova , M. G. Kozlov

We develop the theory of the resonant formation of coupled topological-collective coherent modes in the presence of a quantized trap and classical external field. The coupling between the topological and the collective modes can be linear…

Statistical Mechanics · Physics 2007-05-23 Aranya B Bhattacherjee
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