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Excited states in single quantum dots (QDs) have been shown to be useful for spin state initialization and manipulation. For scalable quantum information processing it is necessary to have multiple spins interacting. Therefore, we present…

The calculation of molecular excited states is critically important to decipher a plethora of molecular properties. In this manuscript, we develop an equation of motion formalism on top of a bi-exponentially parametrized ground state…

Chemical Physics · Physics 2024-01-09 Anish Chakraborty , Pradipta Kumar Samanta , Rahul Maitra

A simple approximation to shell model is proposed in which the low energy excitation spectra corresponds to the identical nucleons occupying the same single particle states where they preferred to form pairs for the ground states. We call…

Nuclear Theory · Physics 2008-10-08 S. Haq , Y. Sadeq , I. M. Hamammu

The analysis of correlation energy of the simplest first approximation of a variational method for the intrashell states of two-electron atoms is the purpose of the present work. This method allows to divide energy of atom on Coulomb and…

Atomic Physics · Physics 2008-10-23 V. V. Kavera

We present an ab initio correlated approach to study molecules that interact strongly with quantum fields in an optical cavity. Quantum electrodynamics coupled cluster theory provides a non-perturbative description of cavity-induced effects…

Chemical Physics · Physics 2020-12-07 Tor S. Haugland , Enrico Ronca , Eirik F. Kjønstad , Angel Rubio , Henrik Koch

In this contribution, we report on recent progress in coupled-cluster simulations of open-shell atomic nuclei using interactions consistently derived from chiral effective field theory. In particular, we compare different coupled-cluster…

The simulation of molecular electronic structure is an important application of quantum devices. Recently, it has been shown that quantum devices can be effectively combined with classical supercomputing centers in the context of the…

Quantum Physics · Physics 2025-02-28 Stefano Barison , Javier Robledo Moreno , Mario Motta

The aim of this work is to develop the relevant formalism for performing coupled-cluster (CC) calculations in nuclear matter and neutron star matter, including thereby important correlations to infinite order in the interaction and testing…

Nuclear Theory · Physics 2013-11-18 G. Baardsen , A. Ekström , G. Hagen , M. Hjorth-Jensen

We use the coupled cluster expansion ($\exp(S)$ method) to generate the complete ground state correlations due to the NN interaction. Part of this procedure is the calculation of the two-body G matrix inside the nucleus in which it is being…

Nuclear Theory · Physics 2009-10-31 Jochen H. Heisenberg , Bogdan. Mihaila

Electrodynamical coupled cluster (CC) methodologies have been formulated employing standard QED Hamiltonian that is written in Coulomb gauge while using the DF and the MCDF pictures of the matter field for closed-shell and open-shell cases…

Quantum Physics · Physics 2024-01-15 Sambhu N. Datta

We present a near-linear scaling formulation of the explicitly-correlated coupled-cluster singles and doubles with perturbative triples method (CCSD(T)$_{\overline{\text{F12}}}$) for high-spin states of open-shell species. The approach is…

Chemical Physics · Physics 2024-07-30 Ashutosh Kumar , Frank Neese , Edward F. Valeev

The Gamow shell model provides the open quantum system formulation of nuclear shell model. In the coupled-channel representation, Gamow shell model provides the unified theory of nuclear structure and reactions which is well suited for the…

Nuclear Theory · Physics 2026-03-16 J. P. Linares Fernandez , N. Michel , M. Płoszajczak

Introducing an active space approximation is inevitable for the quantum computations of chemical systems. However, this approximation ignores the electron correlations related to non-active orbitals. Here, we propose a computational method…

Quantum Physics · Physics 2024-06-06 Luca Erhart , Yuichiro Yoshida , Viktor Khinevich , Wataru Mizukami

The equation of motion coupled cluster singles and doubles model (EOM-CCSD) is an accurate, black-box correlated electronic structure approach to investigate electronically excited states and electron attachment or detachment processes. It…

Chemical Physics · Physics 2023-09-18 Loïc Halbert , Andre Severo Pereira Gomes

We reexamine $\Delta$CCSD, a state-specific coupled-cluster (CC) with single and double excitations (CCSD) approach that targets excited states through the utilization of non-Aufbau determinants. This methodology is particularly efficient…

Chemical Physics · Physics 2024-06-13 Yann Damour , Anthony Scemama , Denis Jacquemin , Fábris Kossoski , Pierre-François Loos

We investigated structures of low-lying $0s$-orbit $\Lambda$ states in $p$-shell $\Lambda$ hypernuclei ($^A_\Lambda Z$) by applying microscopic cluster models for nuclear structure and a single-channel folding potential model for a…

Nuclear Theory · Physics 2018-02-28 Yoshiko Kanada-En'yo

The binding energies of the ground states and several excited states related to single-particle and -hole states in nuclei around ^{16}O are calculated taking charge dependence into account. Effective interactions on the particle basis are…

Nuclear Theory · Physics 2009-11-10 S. Fujii , R. Okamoto , K. Suzuki

We employ the closed-shell perturbed relativistic coupled-cluster (RCC) theory developed by us earlier [Phys. Rev. A {\bf 77}, 062516 (2008)] to evaluate the ground state static electric dipole polarizabilities (\alpha s) of several atomic…

Atomic Physics · Physics 2013-12-09 Yashpal Singh , B. K. Sahoo , B. P. Das

We calculate the energies of ground and three low lying excited states of confined helium atom centered in an impenetrable spherical box. We perform the calculation by employing variational method with two-parameter variational forms for…

Atomic Physics · Physics 2009-11-11 Arup Banerjee , C. Kamal , Avijit Chowdhury

Minimum energy conical intersections can be used to rationalize photochemical processes. In this Letter, we examine an algorithm to locate these structures that does not require the evaluation of nonadiabatic coupling vectors, showing that…

Chemical Physics · Physics 2024-11-15 Sara Angelico , Eirik F. Kjønstad , Henrik Koch