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We employ \textit{ab initio} methods of quantum chemistry to investigate spin-1/2 fermions interacting via a two-body contact potential in a one-dimensional harmonic trap. The convergence of the total energy with the size of the…

The convergence of a recently proposed coupled cluster (CC) family of perturbation series [Eriksen, J. J. et al., J. Chem. Phys. 140, 064108 (2014)], in which the energetic difference between two CC models - a low-level parent and a…

Chemical Physics · Physics 2017-01-18 Janus Juul Eriksen , Kasper Kristensen , Devin A. Matthews , Poul Jørgensen , Jeppe Olsen

We have designed a new multi-scale approach for Strongly Correlated Systems by combining the Dynamical Cluster Approximation (DCA) and the recently introduced dual-fermion formalism. This approach employs an exact mapping from a real…

Strongly Correlated Electrons · Physics 2011-10-12 S. -X. Yang , H. Fotso , H. Hafermann , K. -M. Tam , J. Moreno , T. Pruschke , M. Jarrell

Atomistic-to-Continuum (AtC) coupling methods are a novel means of computing the properties of a discrete crystal structure, such as those containing defects, that combine the accuracy of an atomistic (fully discrete) model with the…

Numerical Analysis · Mathematics 2013-09-25 Derek Olson , Pavel Bochev , Mitchell Luskin , Alexander V. Shapeev

A systematic comparison of three approximate self-interaction corrections (SICs), Perdew-Zunger SIC, Lundin-Eriksson SIC and extended Fermi-Amaldi SIC, is performed for a model Hamiltonian whose exact many-body solution and exact…

Materials Science · Physics 2008-07-18 Daniel Vieira , K. Capelle

We introduce a black-box auxiliary field quantum Monte Carlo (AFQMC) approach to perform highly accurate electronic structure calculations using configuration interaction singles and doubles (CISD) trial states. This method consistently…

We have performed systematic large-scale all-electron correlated calculations on boron clusters B$_{n}$(n=2--5), to study their linear optical absorption spectra. Several possible isomers of each cluster were considered, and their…

Atomic and Molecular Clusters · Physics 2012-08-27 Ravindra Shinde , Alok Shukla

A version of the method of accurate calculations for few valence-electron atoms which combines linearized single-double coupled cluster method with the configuration interaction technique is presented. The use of the method is illustrated…

Atomic Physics · Physics 2015-06-19 V. A. Dzuba

We present a comprehensive theoretical study of the physical phenomena that determine the relative energies of the three of the lowest electronic states of each of the square-planar copper complexes $\cucl$, $\cunh$ and $\cuwater$, and…

Strongly Correlated Electrons · Physics 2018-06-14 Emmanuel Giner , David Tew , Yann Garniron , Ali Alavi

For multivariate data, tandem clustering is a well-known technique aiming to improve cluster identification through initial dimension reduction. Nevertheless, the usual approach using principal component analysis (PCA) has been criticized…

Methodology · Statistics 2024-03-26 Andreas Alfons , Aurore Archimbaud , Klaus Nordhausen , Anne Ruiz-Gazen

Recent years have seen the development of two types of non-local extensions to the single-site dynamical mean field theory. On one hand, cluster approximations, such as the dynamical cluster approximation, recover short-range…

Strongly Correlated Electrons · Physics 2018-03-21 Sergei Iskakov , Hanna Terletska , Emanuel Gull

Contrary to standard coupled cluster doubles (CCD) and Brueckner doubles (BD), singlet-paired analogues of CCD and BD (denoted here as CCD0 and BD0) do not break down when static correlation is present, but neglect substantial amounts of…

Adapting a veritable many-body method to a system of non-interacting particles (NIP), while being trivial from a physical point of view, can be of interest with regard to methodological aspects. In this article we study the NIP versions of…

Chemical Physics · Physics 2023-11-07 Jochen Schirmer

Significant inter-symbol interference (ISI) challenges the achievement of reliable, high data-rate molecular communication via diffusion. In this paper, a hybrid modulation based on pulse position and concentration is proposed to mitigate…

Information Theory · Computer Science 2021-04-21 Mustafa Can Gursoy , Daewon Seo , Urbashi Mitra

In order to explore the effects of high levels of electron correlation on the real-time coupled cluster formalism and algorithmic behavior, we introduce a time-dependent implementation of the CC3 singles, doubles and approximate triples…

Chemical Physics · Physics 2025-01-23 Zhe Wang , Håkon Emil Kristiansen , Thomas Bondo Pedersen , T. Daniel Crawford

Adjoint-based design optimizations are usually computationally expensive and those costs scale with resolution. To address this, researchers have proposed machine learning approaches for inverse design that can predict higher-resolution…

Machine Learning · Computer Science 2024-08-19 Milad Habibi , Mark Fuge

We apply the recently developed dual fermion algorithm for disordered interacting systems to the Anderson-Hubbard model. This algorithm is compared with dynamical cluster approximation calculations for a one-dimensional system to establish…

Strongly Correlated Electrons · Physics 2017-01-24 P. Haase , S. -X. Yang , T. Pruschke , J. Moreno , M. Jarrell

We present an excited-state-specific coupled-cluster approach in which both the molecular orbitals and cluster amplitudes are optimized for an individual excited state. The theory is formulated via a pseudoprojection of the traditional…

Chemical Physics · Physics 2023-11-27 Harrison Tuckman , Eric Neuscamman

Recent disagreement between state-of-the-art quantum chemical methods, coupled cluster with single, double and perturbative triples excitations and fixed-node diffusion Monte Carlo, calls for systematic examination of possible sources of…

Chemical Physics · Physics 2025-05-14 S. Lambie , C. Rickert , D. Usvyat , A. Alavi , D. Kats

Adaptive atomistic/continuum (a/c) coupling method is an important method for the simulation of material and atomistic systems with defects to achieve the balance of accuracy and efficiency. Residual based a posteriori error estimator is…

Numerical Analysis · Mathematics 2022-11-28 Yangshuai Wang , Hao Wang