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Quantum periodic cluster methods for strongly correlated electron systems are reformulated and developed. The reformulation and development are based on a canonical transformation which periodizes the fermions in the cluster space. The…

Strongly Correlated Electrons · Physics 2007-05-23 Tran Minh-Tien

Coupled-cluster theory with single and double excitations (CCSD) is a promising ab initio method for the electronic structure of three-dimensional metals, for which second-order perturbation theory (MP2) diverges in the thermodynamic limit.…

Materials Science · Physics 2021-06-16 James M. Callahan , Malte F. Lange , Timothy C. Berkelbach

The pair-coupled-cluster doubles (pCCD) method has emerged as a viable approach for quantum-chemical studies of strongly correlated systems. Despite its lower formal scaling (O(N$^4$)) compared to other versions of coupled cluster (CC)…

Chemical Physics · Physics 2026-04-17 Rahul Chakraborty , Paweł Tecmer

In this work, we mainly present the optimal convergence rates of the temporally second-order finite element scheme for solving the electrohydrodynamic equation. Suffering from the highly coupled nonlinearity, the convergence analysis of the…

Numerical Analysis · Mathematics 2025-05-06 Shengfeng Wang , Zeyu Xia , Maojun Li

Relativistic Continuum Random Phase Approximation (CRPA) is used to investigate collective excitation phenomena in several spherical nuclei along the periodic table. We start from relativistic mean field calculations based on a covariant…

Nuclear Theory · Physics 2011-03-21 J. Daoutidis , P. Ring

Succeeding our previous finding about coherent interference of the resonant states of CO^- formed by the low-energy electron attachment [Phys. Rev. A 88, 012708 (2013)], here we provide more evidences of the coherent interference, in…

Atomic and Molecular Clusters · Physics 2015-09-02 Xu-Dong Wang , Chuan-Jin Xuan , Yi Luo , Shan Xi Tian

The Coupled Cluster (CC) method is used to compute the electronic correlation energy in atoms and molecules and often leads to highly accurate results. However, due to its single-reference nature, standard CC in its projected form fails to…

A novel approach to rapidly converging high-level coupled-cluster (CC) energetics in an automated fashion is proposed. The key idea is an adaptive selection of the excitation manifolds defining higher-than-two-body components of the cluster…

Chemical Physics · Physics 2023-08-25 Karthik Gururangan , Piotr Piecuch

The accurate calculation of excited state properties of interacting electrons in the condensed phase is an immense challenge in computational physics. Here, we use state-of-the-art equation-of-motion coupled-cluster theory with single and…

Chemical Physics · Physics 2019-07-10 Alan M. Lewis , Timothy C. Berkelbach

In this work we investigate the ability of the cumulant expansion (CE) to capture one-particle spectral information in electron-phonon coupled systems at both zero and finite temperatures. In particular, we present a comprehensive study of…

Chemical Physics · Physics 2022-06-09 Paul J. Robinson , Ian S. Dunn , David R. Reichman

We revisit the connection between equation-of-motion coupled cluster (EOM-CC) and random phase approximation (RPA) explored recently by Berkelbach [J. Chem. Phys. 149, 041103 (2018)] and unify various methodological aspects of these diverse…

Chemical Physics · Physics 2020-12-17 Varun Rishi , Ajith Perera , Rodney J. Bartlett

The electron affinity (EA) of superheavy element Og is calculated by the use of the relativistic Fock-space coupled cluster (FSCC) and configuration interaction methods. The FSCC cluster operator expansion included single, double, and…

Approximate full configuration interaction (FCI) calculations have recently become tractable for systems of unforeseen size thanks to stochastic and adaptive approximations to the exponentially scaling FCI problem. The result of an FCI…

Strongly Correlated Electrons · Physics 2017-10-25 Susi Lehtola , Norm M. Tubman , K. Birgitta Whaley , Martin Head-Gordon

A new method that accurately describes strongly correlated states and captures dynamical correlation is presented. It is derived as a modification of coupled-cluster theory with single and double excitations (CCSD) through consideration of…

Chemical Physics · Physics 2013-07-15 Daniel Kats , Frederick R. Manby

Accurately describing strong electron correlation in complex systems remains a prominent challenge in computational chemistry as near-term quantum algorithms treating total correlation often require prohibitively deep circuits. Here we…

Computational Engineering, Finance, and Science · Computer Science 2026-04-21 Zhanou Liu , Yuhao Chen , Yingjin Ma , Xiao He , Yuxin Deng

Recent relativistic coupled-cluster (RCC) calculations of electric dipole moments (EDMs) of diamagnetic atoms due to parity and time-reversal violating (P,T-odd) interactions, that are essential ingredients for probing new physics beyond…

Atomic Physics · Physics 2018-05-23 B. K. Sahoo , B. P. Das

We study the Complex Absorbing Potential (CAP) Method in computing quantum resonances of width $c(h) = O(h^N)$, $N\gg1$. We show that up to $h^{-M}\sqrt{c(h)} +\Oh$ error, $M\gg1$, resonances are perturbed eigenvalues of the CAP Hamiltonian…

Mathematical Physics · Physics 2007-05-23 Plamen Stefanov

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

The near-threshold clustering phenomenon is well understood by the low-energy universality, for shallow bound states below the threshold. Nevertheless, the characteristics of resonances slightly above the threshold still lack thorough…

High Energy Physics - Phenomenology · Physics 2024-08-02 Tomona Kinugawa , Tetsuo Hyodo

We extend the single-site coherent potential approximation (CPA) to include the effects of non-local disorder correlations (alloy short-range order) on the electronic structure of random alloy systems. This is achieved by mapping the…

Strongly Correlated Electrons · Physics 2009-11-10 M. S. Laad , L. Craco