English
Related papers

Related papers: Can single-reference coupled cluster theory descri…

200 papers

For noncovalent interactions, it is generally assumed that CCSD(T) is nearly the exact solution within the 1-particle basis set. For the S66 noncovalent interactions benchmark, we present for the majority of species CCSDT and CCSDT(Q)…

Chemical Physics · Physics 2025-01-22 Emmanouil Semidalas , A. Daniel Boese , Jan M. L. Martin

Deep clustering (DC) has become the state-of-the-art for unsupervised clustering. In principle, DC represents a variety of unsupervised methods that jointly learn the underlying clusters and the latent representation directly from…

Machine Learning · Computer Science 2020-05-22 Lele Cao , Sahar Asadi , Wenfei Zhu , Christian Schmidli , Michael Sjöberg

We have studied electron correlations in the doped two-dimensional (2D) Hubbard model by using the coupled-cluster method (CCM) to investigate whether or not the method can be applied to correct the independent particle approximations…

Strongly Correlated Electrons · Physics 2009-10-31 Yoshihiro Asai , Hideki Katagiri

One of the commonly used chemical-inspired approaches in variational quantum computing is the unitary coupled-cluster (UCC) ansatze. Despite being a systematic way of approaching the exact limit, the number of parameters in the standard UCC…

Quantum Physics · Physics 2023-06-06 Shashank G Mehendale , Bo Peng , Niranjan Govind , Yuri Alexeev

Arguably the most widely used approaches for obtaining highly accurate molecular ground-state energies are coupled cluster methods. Despite introducing two layers of approximation, a linear and a nonlinear one, coupled cluster methods…

Numerical Analysis · Mathematics 2026-05-22 Jonas Beck , Benjamin Stamm

We present the quantum-selected configuration interaction-tailored coupled-cluster (QSCI-TCC) method, a hybrid quantum-classical scheme that tailors coupled-cluster (CC) theory with a quantum-selected configuration interaction (QSCI) wave…

Chemical Physics · Physics 2025-06-23 Luca Erhart , Yuichiro Yoshida , Wataru Mizukami

An extensive analysis has been carried out of the performance of standard families of basis sets with the hierarchy of coupled cluster methods CC2, CCSD, CC3 and CCSDT in computing selected Oxygen, Carbon and Nitrogen K-edge (vertical) core…

Chemical Physics · Physics 2019-08-13 Johanna P. Carbone , Lan Cheng , Rolf H. Myhre , Devin Matthews , Henrik Koch , Sonia Coriani

Traditional clustering methods often perform clustering with low-level indiscriminative representations and ignore relationships between patterns, resulting in slight achievements in the era of deep learning. To handle this problem, we…

Machine Learning · Computer Science 2019-05-07 Jianlong Chang , Yiwen Guo , Lingfeng Wang , Gaofeng Meng , Shiming Xiang , Chunhong Pan

The Cauchy combination test (CCT) is widely used because it gives a closed-form combined $p$-value and is known to be asymptotically valid as the nominal level $\alpha\downarrow0$ under broad dependence structures. We study a different…

Statistics Theory · Mathematics 2026-03-25 Hirofumi Ota

Clustering multivariate time series data is a crucial task in many domains, as it enables the identification of meaningful patterns and groups in time-evolving data. Traditional approaches, such as crisp clustering, rely on the assumption…

Methodology · Statistics 2025-09-05 Ziling Ma , Ángel López-Oriona , Hernando Ombao , Ying Sun

The focus of this work is OS-CCSD-SPT(2), which is a second-order similarity transformed perturbation theory correction to opposite spin coupled cluster singles doubles, where in the latter the same-spin amplitudes are removed and the…

Chemical Physics · Physics 2020-03-16 David W. Small

We extend our assessment of the potential of perturbative coupled cluster (CC) expansions for a test set of open-shell atoms and organic radicals to the description of quadruple excitations. Namely, the second- through sixth-order models of…

Chemical Physics · Physics 2016-05-17 Janus J. Eriksen , Devin A. Matthews , Poul Jørgensen , Jürgen Gauss

Guided by perturbative analysis, we improve the accuracy of Aufbau suppressed coupled cluster theory in simple single excitations, multi-configurational single excitations, and charge transfer excitations while keeping the cost of its…

Chemical Physics · Physics 2025-03-26 Harrison Tuckman , Ziheng Ma , Eric Neuscamman

An entangled state is said to be $m$-uniform if the reduced density matrix of any $m$ qubits is maximally mixed. This is intimately linked to pure quantum error correction codes (QECCs), which allow not only to correct errors, but also to…

Quantum Physics · Physics 2023-09-01 Sowrabh Sudevan , Daniel Azses , Emanuele G. Dalla Torre , Eran Sela , Sourin Das

A new state specific correlation correction to configuration interaction singles (CIS) excitation energies is preseted using coupled cluster perturbation theory (CCPT). General expressions for CIS-CCPT are derived and expanded explicitly to…

Chemical Physics · Physics 2015-06-19 Jason N. Byrd , Victor F. Lotrich , Rodney J. Bartlett

We continue the investigation of problems concerning correlation clustering or clustering with qualitative information, which is a clustering formulation that has been studied recently. The basic setup here is that we are given as input a…

Data Structures and Algorithms · Computer Science 2007-05-23 Ioannis Giotis , Venkatesan Guruswami

Correlation clustering is a well-studied problem, first proposed by Bansal, Blum, and Chawla [Mach. Learn. '04]. The input is an unweighted, undirected graph. The problem is to cluster the vertices so as to minimize the number of edges…

Data Structures and Algorithms · Computer Science 2026-05-12 Nairen Cao , Vincent Cohen-Addad , Euiwoong Lee , Shi Li , David Rasmussen Lolck , Alantha Newman , Mikkel Thorup , Lukas Vogl , Shuyi Yan , Hanwen Zhang

Clustering under pairwise constraints is an important knowledge discovery tool that enables the learning of appropriate kernels or distance metrics to improve clustering performance. These pairwise constraints, which come in the form of…

Machine Learning · Computer Science 2022-03-24 Benedikt Boecking , Vincent Jeanselme , Artur Dubrawski

We investigate 1D and 2D cluster states under local decoherence to assess the robustness of their mixed-state subsystem symmetry-protected topological (SSPT) order. By exactly computing fidelity correlators via dimensional reduction of…

Quantum Physics · Physics 2025-04-24 Seunghun Lee , Eun-Gook Moon

We present a detailed description of an architecture for fault-tolerant quantum computation, which is based on the cluster model of encoded qubits. In this cluster-based architecture, concatenated computation is implemented in a quite…

Quantum Physics · Physics 2010-12-30 Keisuke Fujii , Katsuji Yamamoto