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Related papers: Degenerate coupled-cluster theory

200 papers

In spite of missing dynamical correlations, the projected generator coordinate method (PGCM) was recently shown to be a suitable method to tackle the low-lying spectroscopy of complex nuclei. Still, describing absolute binding energies and…

A unitary coupled-cluster (UCC) form for the wavefunction in the variational quantum eigensolver has been suggested as a systematic way to go beyond the mean-field approximation and include electron correlation in solving quantum chemistry…

Quantum Physics · Physics 2018-09-12 Ilya G. Ryabinkin , Tzu-Ching Yen , Scott N. Genin , Artur F. Izmaylov

We introduce coupled-cluster (CC) theory for the numerical study of the normal state of two-component, dilute Fermi gases with attractive, short-range interactions at zero temperature. We focus on CC theory with double excitations (CCD) and…

Quantum Gases · Physics 2022-09-12 James M. Callahan , John Sous , Timothy C. Berkelbach

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

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

The hierarchy of Green functions for (quasi)degenerate systems, presented in cond-mat/0308058, is calculated in detail for the case of a system with closed shells plus a single electron in a two-fold degenerate level. The complete hierarchy…

Strongly Correlated Electrons · Physics 2007-05-23 Christian Brouder

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

We present the data-driven coupled-cluster deep network (DDCCNet), a family of multitask, physics-enhanced deep learning architectures designed to predict coupled-cluster singles and doubles (CCSD) amplitudes and correlation energies from…

Chemical Physics · Physics 2026-02-03 P. D. Varuna S. Pathirage , Konstantinos D. Vogiatzis

In this Communication, we provide numerical evidence indicating that the standard single-reference coupled-cluster (CC) energies can be calculated alternatively to its copybook definition. We demonstrate that the CC energies can be…

Quantum Physics · Physics 2023-02-15 Karol Kowalski

Nuclear physics seeks to describe both bound and unbound states within a unified predictive framework. While coordinate-space Quantum Monte Carlo (QMC) methods have successfully computed bound states for systems with $A \leq 12$, their…

Nuclear Theory · Physics 2025-02-27 Abraham R. Flores , Kenneth M. Nollett , Maria Piarulli

We extend coupled-cluster theory performed on top of a Slater determinant breaking rotational symmetry to allow for the exact restoration of the angular momentum at any truncation order. The main objective relates to the description of…

Nuclear Theory · Physics 2015-06-22 T. Duguet

While restricted single-reference coupled cluster theory truncated to singles and doubles (CCSD) provides very accurate results for weakly correlated systems, it usually fails in the presence of static or strong correlation. This failure is…

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

We show that short-range correlations have a dramatic impact on the steady-state phase diagram of quantum driven-dissipative systems. This effect, never observed in equilibrium, follows from the fact that ordering in the steady state is of…

Statistical Mechanics · Physics 2016-07-29 Jiasen Jin , Alberto Biella , Oscar Viyuela , Leonardo Mazza , Jonathan Keeling , Rosario Fazio , Davide Rossini

Striving to define very accurate vertical transition energies, we perform both high-level coupled cluster (CC) calculations (up to CCSDTQP) and selected configuration interaction (sCI) calculations (up to several millions of determinants)…

We study many-body correlations in the ground states of a general quantum system of bosons or fermions by including an additional Jastrow function in our ecently proposed variational coupled-cluster method. Our approach combines the…

Strongly Correlated Electrons · Physics 2009-11-13 Y. Xian

In spin-adapted open-shell coupled cluster (CC) theory, the choice of spin-free spatial substitution operators is generally not unique. Due to an increasing linear dependence of the cluster operator (with increasing substitution level), the…

Chemical Physics · Physics 2022-04-27 Nils Herrmann , Michael Hanrath

We present two efficient and intruder-free methods for treating dynamic correlation on top of general multi-configuration reference wave functions---including such as obtained by the density matrix renormalization group (DMRG) with large…

Chemical Physics · Physics 2016-09-13 Sandeep Sharma , Gerald Knizia , Sheng Guo , Ali Alavi

We introduce the multistate iterative qubit coupled cluster (MS-iQCC) method, a quantum-inspired algorithm that runs efficiently on classical hardware and is designed to predict both ground and excited electronic states of molecules.…

Chemical Physics · Physics 2026-01-05 Robert A. Lang , Shashank G. Mehendale , Ilya G. Ryabinkin , Artur F. Izmaylov

An implementation of coupled-cluster (CC) theory to treat atoms and molecules in finite magnetic fields is presented. The main challenges stem from the magnetic-field dependence in the Hamiltonian, or, more precisely, the appearance of the…

Chemical Physics · Physics 2015-09-02 Stella Stopkowicz , Jürgen Gauss , Kai K. Lange , Erik I. Tellgren , Trygve Helgaker

I review the quantum theory of the electron moving in a random environment. First, the quantum mechanics of individual particles scattered on a random potential is discussed. The quantum-mechanical description is extended to many-body…

Disordered Systems and Neural Networks · Physics 2021-09-13 Václav Janiš