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Related papers: The Coupled-Cluster Formalism - a Mathematical Per…

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The mathematical foundation of the so-called extended coupled-cluster method for the solution of the many-fermion Schr\"odinger equation is here developed. We prove an existence and uniqueness result, both in the full infinite-dimensional…

Numerical Analysis · Mathematics 2017-02-15 Andre Laestadius , Simen Kvaal

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

In a series of two articles, we propose a comprehensive mathematical framework for Coupled-Cluster-type methods. These methods aim at accurately solving the many-body Schrodinger equation. In this first part, we rigorously describe the…

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

In this tutorial-style review we discuss basic concepts of coupled cluster theory and recent developments that increase its computational efficiency for calculations of molecules, solids and materials in general. We will touch upon the…

Materials Science · Physics 2020-04-15 Igor Ying Zhang , Andreas Grüneis

A wide class of coupled-cluster methods is introduced, based on Arponen's extended coupled-cluster theory. This class of methods is formulated in terms of a coordinate transformation of the cluster operators. The mathematical framework for…

Chemical Physics · Physics 2020-12-02 Simen Kvaal , Andre Laestadius , Tilmann Bodenstein

In this paper, we have analysed the time series associated with the iterative scheme of a double similarity transformed Coupled Cluster theory. The coupled iterative scheme to solve the ground state Schr{\"o}dinger equation is cast as a…

Statistical Mechanics · Physics 2020-07-29 Valay Agarawal , Anish Chakraborty , Rahul Maitra

Coupled cluster theory produced arguably the most widely used high-accuracy computational quantum chemistry methods. Despite the approach's overall great computational success, its mathematical understanding is so far limited to results…

Algebraic Geometry · Mathematics 2024-03-29 Fabian M. Faulstich , Mathias Oster

It is shown how to adapt the non-perturbative coupled cluster method of many-body theory so that it may be successfully applied to Hamiltonian lattice $SU(N)$ gauge theories. The procedure involves first writing the wavefunctions for the…

High Energy Physics - Lattice · Physics 2009-10-22 C. H. Llewellyn Smith , N. J. Watson

In quantum chemistry, one of the most important challenges is the static correlation problem when solving the electronic Schr\"odinger equation for molecules in the Born--Oppenheimer approximation. In this article, we analyze the tailored…

Numerical Analysis · Mathematics 2019-11-21 Fabian M. Faulstich , Andre Laestadius , Örs Legeza , Reinhold Schneider , Simen Kvaal

Coupled cluster theory is one of the most accurate electronic structure methods for predicting ground and excited state chemistry. However, the presence of numerical artifacts at electronic degeneracies, such as complex energies, has made…

Chemical Physics · Physics 2024-05-16 Eirik F. Kjønstad , Sara Angelico , Henrik Koch

We develop a coupled-cluster theory for bosonic mixtures of binary species in external traps, providing a promising theoretical approach to demonstrate highly accurately the many-body physics of mixtures of Bose-Einstein condensates. The…

Quantum Gases · Physics 2024-02-01 Anal Bhowmik , Ofir E. Alon

The coupled cluster iteration scheme for determining the cluster amplitudes involves a set of nonlinearly coupled difference equations. In the space spanned by the amplitudes, the set of equations are analysed as a multivariate…

A dynamical formulation of coupled cluster theory is derived using a variational principle. By allowing time-dependent single-particle functions, a high degree of adaptivity is introduced, allowing complex systems to be simulated with high…

Quantum Physics · Physics 2014-11-25 Simen Kvaal

An electrodynamical coupled cluster (CC) methodology starting from a covariant formalism and an equal time approximation, and finally based on the Dirac-Fock picture of the electron and positron fields and Coulomb gauge, is given here. The…

Atomic Physics · Physics 2019-04-30 Sambhu N. Datta

In the context of clustering, we consider a generative model in a Euclidean ambient space with clusters of different shapes, dimensions, sizes and densities. In an asymptotic setting where the number of points becomes large, we obtain…

Machine Learning · Statistics 2009-09-15 Ery Arias-Castro

We consider a new formulation of the stochastic coupled cluster method in terms of the similarity transformed Hamiltonian. We show that improvement in the granularity with which the wavefunction is represented results in a reduction in the…

Chemical Physics · Physics 2016-02-02 Ruth S. T. Franklin , James S. Spencer , Alberto Zoccante , Alex J. W. Thom

Methods which aim at universal applicability must be able to describe both weak and strong electronic correlation with equal facility. Such methods are in short supply. The combination of symmetry projection for strong correlation and…

Chemical Physics · Physics 2020-05-14 Yiheng Qiu , Thomas M. Henderson , Jinmo Zhao , Gustavo E. Scuseria

We consider the sampling of the coupled cluster expansion within stochastic coupled cluster theory. Observing the limitations of previous approaches due to the inherently non-linear behaviour of a coupled cluster wavefunction representation…

Chemical Physics · Physics 2018-08-14 Charles J. C. Scott , Alex J. W. Thom

We apply Coupled Cluster Method to a strongly correlated lattice and develop the Spectral Coupled Cluster equations by finding an approximation to the resolvent operator, that gives the spectral response for an certain class of probe…

Strongly Correlated Electrons · Physics 2012-07-03 Alessandro Mirone

Quantum Clustering is a powerful method to detect clusters in data with mixed density. However, it is very sensitive to a length parameter that is inherent to the Schr\"odinger equation. In addition, linking data points into clusters…

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