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This paper explores the problem of clustering ensemble, which aims to combine multiple base clusterings to produce better performance than that of the individual one. The existing clustering ensemble methods generally construct a…

Machine Learning · Computer Science 2020-12-17 Yuheng Jia , Hui Liu , Junhui Hou , Qingfu Zhang

We propose a simple cluster-based method with application to calculations of Compton profile anisotropies of ice. The convergence of the method is checked with respect to Crystal95 results. Increasing both basis-set quality and cluster…

Chemical Physics · Physics 2016-09-08 Sebastien Ragot , Jean-Michel Gillet , Pierre J. Becker

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…

A method is proposed to improve the accuracy of approximate techniques for strongly correlated electrons that use reduced Hilbert spaces. As a first step, the method involves a change of basis that incorporates exactly part of the short…

Statistical Mechanics · Physics 2009-10-30 E. Dagotto , G. B. Martins , J. Riera , A. L. Malvezzi , C. Gazza

The practical application of quantum technologies to chemical problems faces significant challenges, particularly in the treatment of realistic basis sets and the accurate inclusion of electron correlation effects. A direct approach to…

The performance of most the clustering methods hinges on the used pairwise affinity, which is usually denoted by a similarity matrix. However, the pairwise similarity is notoriously known for its vulnerability of noise contamination or the…

Machine Learning · Computer Science 2020-06-29 Hong Peng , Yu Hu , Jiazhou Chen , Haiyan Wang , Yang Li , Hongmin Cai

We present a new implementation of DMRG-based tailored coupled clusters method (TCCSD), which employs the domain-based local pair natural orbital approach (DLPNO-TCCSD). Compared to the previous LPNO version of the method, the new…

Chemical Physics · Physics 2020-05-08 Jakub Lang , Andrej Antalík , Libor Veis , Jan Brandejs , Jiří Brabec , Örs Legeza , Jiří Pittner

The cluster-in-molecule (CIM) local correlation approach with an accurate distant pair correlation energy correction is presented. For large systems, the inclusion of distant pair correlation energies is essential for the accurate…

Chemical Physics · Physics 2020-08-06 Zhigang Ni , Yang Guo , Frank Neese , Wei Li , Shuhua Li

An adaptation of the full configuration interaction quantum Monte Carlo (FCIQMC) method is presented, for correlated electron problems containing heavy elements and the presence of significant relativistic effects. The modified algorithm…

Chemical Physics · Physics 2020-10-26 Robert J. Anderson , George H. Booth

An efficient approach to calculate approximate pure-state and transition reduced density matrices in the framework of the multireference relativistic Fock-space coupled cluster (FS CC) theory is proposed. The method is based on the…

Computational Physics · Physics 2025-06-12 Alexander V. Oleynichenko , Andrei Zaitsevskii , Leonid V. Skripnikov , Ephraim Eliav

We consider the MAP-MRF inference task, that is, minimizing a function of discrete variables represented as a sum of unary and pairwise terms. A prominent approach for tackling this NP-hard problem in practice is to solve its natural LP…

Data Structures and Algorithms · Computer Science 2026-05-14 Asaf Lev-Ran , Pavel Arkhipov , Vladimir Kolmogorov

We present a self consistent method to perfom a joint analysis of Sunyaev-Zel'dovich and weak gravitational lensing observation of galaxy clusters. The spatial distribution of the cluster main constituents is described by a perturbative…

Astrophysics · Physics 2009-11-06 O. Doré , F. R. Bouchet , Y. Mellier , R. Teyssier

Doubly occupied configuration interaction (DOCI) with optimized orbitals often accurately describes strong correlations while working in a Hilbert space much smaller than that needed for full configuration interaction. However, the scaling…

Chemical Physics · Physics 2016-02-25 Thomas M. Henderson , Ireneusz W. Bulik , Tamar Stein , Gustavo E. Scuseria

Based on the self-energy-functional approach proposed recently [M. Potthoff, Eur. Phys. J. B 32, 429 (2003)], we present an extension of the cluster-perturbation theory to systems with spontaneously broken symmetry. Our method applies to…

Strongly Correlated Electrons · Physics 2007-05-23 C. Dahnken , M. Aichhorn , W. Hanke , E. Arrigoni , M. Potthoff

We present a perturbative triples correction to the relativistic quadratic unitary coupled cluster singles and doubles (qUCCSD) method, denoted as qUCCSD[T]. The method builds upon the Hermitian structure of the unitary ansatz and employs a…

Chemical Physics · Physics 2025-10-08 Kamal Majee , Ján Šimunek , Jozef Noga , Achintya Kumar Dutta

The recently introduced coupled cluster (CC) downfolding techniques for reducing the dimensionality of quantum many-body problems recast the CC formalism in the form of the renormalization procedure allowing, for the construction of…

Quantum Physics · Physics 2021-11-08 Nicholas P. Bauman , Karol Kowalski

Conventional clustering methods based on pairwise affinity usually suffer from the concentration effect while processing huge dimensional features yet low sample sizes data, resulting in inaccuracy to encode the sample proximity and…

Machine Learning · Computer Science 2023-02-06 Hongmin Cai , Fei Qi , Junyu Li , Yu Hu , Yue Zhang , Yiu-ming Cheung , Bin Hu

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 present the coupled-cluster singles and doubles method formulated in terms of truncated pair-natural orbitals (PNO) that are optimized to minimize the effect of truncation. Compared to the standard ground-state PNO coupled-cluster…

Chemical Physics · Physics 2020-06-09 Marjory C. Clement , Jinmei Zhang , Cannada A. Lewis , Chao Yang , Edward F. Valeev

We propose to improve the convergence properties of the single-reference coupled cluster (CC) method through an augmented Lagrangian formalism. The conventional CC method changes a linear high-dimensional eigenvalue problem with exponential…

Computational Physics · Physics 2024-03-26 Fabian M. Faulstich , Yuehaw Khoo , Kangbo Li