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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

We present cluster Monte Carlo algorithms for the $XYZ$ quantum spin models. In the special case of $S=1/2$, the new algorithm can be viewed as a cluster algorithm for the 8-vertex model. As an example, we study the $S=1/2$ $XY$ model in…

Condensed Matter · Physics 2009-10-28 N. Kawashima

We develop a unified approach to the problem of clustering in the three different fields of applications, as indicated in the title the paper. The approach is based on Khintchine's probabilistic method that grew out of the Darwin-Fawler…

Probability · Mathematics 2007-06-13 Gregory Freiman , Boris Granovsky

We develop a cluster expansion to show exponential decay of correlations for quite general single scale spin systems, as they arise in lattice quantum field theory and discretized functional integral representations for observables of…

Mathematical Physics · Physics 2014-11-06 Martin Lohmann

We present a general strategy to extend quantum cluster algorithms for S=1/2 spin systems, such as the loop algorithm, to systems with arbitrary size of spins. In general, the partition function of a high-S spin system is represented in…

Statistical Mechanics · Physics 2009-10-31 Synge Todo , Kiyoshi Kato

We study the cluster recovery problem in the semi-supervised active clustering framework. Given a finite set of input points, and an oracle revealing whether any two points lie in the same cluster, our goal is to recover all clusters…

Machine Learning · Computer Science 2020-11-02 Marco Bressan , Nicolò Cesa-Bianchi , Silvio Lattanzi , Andrea Paudice

In this work we present a coupled cluster based approach to the computation of the spin orbit coupling matrix elements. The working expressions are derived from the quadratic response function with the coupled cluster parametrization, using…

Chemical Physics · Physics 2023-01-11 Aleksandra Maria Tucholska , Michał Lesiuk , Robert Moszynski

The dual exponential coupled cluster (CC) theory proposed by Tribedi et al.[J. Chem. Theory Comput. 2020, 16, 10, 6317-6328] performs significantly better than the coupled cluster theory with singles and doubles excitations (CCSD) due to…

Computational Physics · Physics 2023-07-26 Anish Chakraborty , Rahul Maitra

Unitary coupled cluster (UCC), originally developed as a variational alternative to the popular traditional coupled cluster method, has seen a resurgence as a functional form for use on quantum computers. However, the number of excitors…

Chemical Physics · Physics 2021-01-07 Maria-Andreea Filip , Alex J. W. Thom

A model is constructed in which pair potentials are combined with the cluster expansion method in order to better describe the energetics of structurally relaxed substitutional alloys. The effect of structural relaxations away from the…

Materials Science · Physics 2012-03-06 H. Y. Geng , M. H. F. Sluiter , N. X. Chen

We address binary classification using neural ordinary differential equations from the perspective of simultaneous control of $N$ data points. We consider a single-neuron architecture with parameters fixed as piecewise constant functions of…

Optimization and Control · Mathematics 2025-04-18 Antonio Álvarez-López , Rafael Orive-Illera , Enrique Zuazua

We prove clustering estimates for the truncated correlations, i.e., cumulants of an unbounded spin system on the lattice. We provide a unified treatment, based on cluster expansion techniques, of four different regimes: large mass, small…

Mathematical Physics · Physics 2015-05-13 Abdelmalek Abdesselam , Aldo Procacci , Benedetto Scoppola

Squeezed states of spin systems are an important entangled resource for quantum technologies, particularly quantum metrology and sensing. Here we consider the generation of spin squeezed states by interacting the spins with a dissipative…

Quantum Physics · Physics 2016-05-19 Shane Dooley , Emi Yukawa , Yuichiro Matsuzaki , George C. Knee , William J. Munro , Kae Nemoto

A microscopic derivation of the classical Generalized Constant Coupling (GCC) model for geometrically frustrated magnets is presented. Starting from the classical Heisenberg Hamiltonian, the partition function for clusters with p = 2, 3, 4…

Strongly Correlated Electrons · Physics 2009-11-07 A. J. Garcia-Adeva , D. L. Huber

We present a practical approach to treat static and dynamical correlation accurately in large multi-configurational systems. The static correlation is accounted for using the spin-flip approach which is well known for capturing static…

Strongly Correlated Electrons · Physics 2021-02-08 Oinam Romesh Meitei , Nicholas J. Mayhall

In this work, we investigate the possibility of improving multireference-driven coupled cluster (CC) approaches with an algorithm that iteratively combines complete active space (CAS) calculations with tailored CC and externally corrected…

Chemical Physics · Physics 2025-03-06 Robin Feldmann , Max Mörchen , Jakub Lang , Michał Lesiuk , Markus Reiher

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

Cluster-randomized experiments are widely used due to their logistical convenience and policy relevance. To analyze them properly, we must address the fact that the treatment is assigned at the cluster level instead of the individual level.…

Methodology · Statistics 2021-08-06 Fangzhou Su , Peng Ding

We present a generalization of the recently proposed variational cluster perturbation theory to extended Hubbard models at half filling with repulsive nearest neighbor interaction. The method takes into account short-range correlations…

Strongly Correlated Electrons · Physics 2009-11-10 M. Aichhorn , H. G. Evertz , W. von der Linden , M. Potthoff

In this article, we propose the use of partitioning and clustering methods as an alternative to Gaussian quadrature for stochastic collocation. The key idea is to use cluster centers as the nodes for collocation. In this way, we can extend…

Numerical Analysis · Mathematics 2019-04-16 A. W. Eggels , D. T. Crommelin , J. A. S. Witteveen
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