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The effect of orbital magnetism on the chemical bonding of lateral, two-dimensional artificial molecules is studied in the case of a 2e double quantum dot (artificial molecular hydrogen). It is found that a perpendicular magnetic field…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Constantine Yannouleas , Uzi Landman

The relativistic Hartree-Fock and electron correlation methods without the negative-energy orbital problem are examined on the basis of the quantum electrodynamics (QED) Hamiltonian. First, several QED Hamiltonians previously proposed are…

Chemical Physics · Physics 2023-01-02 Nobuki Inoue , Yoshihiro Watanabe , Haruyuki Nakano

We report a three-dimensional numerical implementation of multiconfiguration time-dependent Hartree-Fock (MCTDHF) based on a multi-resolution Cartesian grid, with no need to assume any symmetry of molecular structure. We successfully…

Computational Physics · Physics 2016-03-23 Ryohto Sawada , Takeshi Sato , Kenichi L. Ishikawa

We introduce highly local basis sets for electronic structure which are very efficient for correlation calculations near the complete basis set limit. Our approach is based on gausslets, recently introduced wavelet-like smooth orthogonal…

Chemical Physics · Physics 2019-02-20 Steven R. White , E. Miles Stoudenmire

An approximate relativistic two-component Hamiltonian for use in molecular electronic structure calculations is derived in the form of a sum of fixed atom-centered kinetic and spin-orbit operators added to the non-relativistic Hamiltonian.…

Chemical Physics · Physics 2019-02-13 Dimitri N. Laikov

Processes related to electronically excited states are central in many areas of science, however accurately determining excited-state energies remains a major challenge in theoretical chemistry. Recently, higher energy stationary states of…

Chemical Physics · Physics 2020-06-05 Hugh G. A. Burton , Alex J. W. Thom , Pierre-François Loos

A path integral ground state approach has been used to estimate the ground-state energy and structural properties of hydrogen fluoride molecules pinned to a one-dimensional lattice. In the simulations, the molecules are assumed to be rigid,…

Chemical Physics · Physics 2023-08-10 Tapas Sahoo , Gautam Gangopadhyay

This study proposes a high-order multi-scale method tailored for time-dependent nonlinear thermo-electro-mechanical coupling problems of composite structures with highly spatial heterogeneity, which incorporate temperature-dependent…

Numerical Analysis · Mathematics 2026-04-22 Hao Dong

Ground state preparation is a central application of quantum algorithms for electronic structure. We introduce the classical reservoir approach, a low cost variational ansatz tailored to near-term hardware, requiring only nearest-neighbor…

Quantum Physics · Physics 2025-12-25 Zekun He , Dominika Zgid , A. F. Kemper , J. K. Freericks

We present here a review of the fundamental topics of Hartree-Fock theory in Quantum Chemistry. From the molecular Hamiltonian, using and discussing the Born-Oppenheimer approximation, we arrive to the Hartree and Hartree-Fock equations for…

Chemical Physics · Physics 2008-11-25 Pablo Echenique , J. L. Alonso

Few-electron systems confined in two-dimensional parabolic quantum dots at high magnetic fields are studied by the Hartree-Fock (HF) and exact diagonalization methods. A generalized multicenter Gaussian basis is proposed in the HF method. A…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 B. Szafran , S. Bednarek , J. Adamowski , M. B. Tavernier , E. Anisimovas , F. M. Peeters

An interacting lattice model describing the subspace spanned by a set of strongly-correlated bands is rigorously coupled to density functional theory to enable ab initio calculations of geometric and topological material properties. The…

Strongly Correlated Electrons · Physics 2019-03-26 Ryan Requist , E. K. U. Gross

This paper addresses the trajectory-tracking problem for a class of electromechanical systems. To this end, the dynamics of the plants are modeled in the so-called port-Hamiltonian framework. Then, the notion of contraction is exploited to…

Systems and Control · Electrical Eng. & Systems 2023-11-14 Najmeh Javanmardi , Pablo Borja , Jacquelien M. A. Scherpen

This article is an introduction to a new approach to first principles electronic structure calculation. The starting point is the Hartree-Fock-Roothaan equation, in which molecular integrals are approximated by polynomials by way of Taylor…

Computational Physics · Physics 2019-07-18 Akihito Kikuchi

We study the interplay between electronic interactions and quasiperiodicity in a one-dimensional narrow-band system, focusing on ground-state and low-energy excitation properties. Using band projection as low-energy effective approach, we…

Strongly Correlated Electrons · Physics 2026-03-17 Flavio Riche , Raul Liquito , Bruno Amorim , Eduardo V. Castro , Pedro Ribeiro , Miguel Gonçalves

A new concept of the molecular structure optimization method based on quantum dynamics computations is presented. Nuclei are treated as quantum mechanical particles, as are electrons, and the many-body wave function of the system is…

A numerical algorithm for studying strongly correlated electron systems is proposed. The groundstate wavefunction is projected out after numerical renormalization procedure in the path integral formalism. The wavefunction is expressed from…

Strongly Correlated Electrons · Physics 2007-05-23 Masatoshi Imada , Tsuyoshi Kashima

We introduce a simple ansatz for the wavefunction of a many-body system based on coupled forward and backward-propagating semiclassical trajectories. This method is primarily aimed at, but not limited to, treating nonequilibrium dynamics in…

Chemical Physics · Physics 2018-05-01 Shunsuke A. Sato , Aaron Kelly , Angel Rubio

The problem of constructing a guaranteed convergent sequence of corrections to the Hartree--Fock ground state energy of a molecule without storing the many-electron wave function is considered. Several methods based on cumulants are…

Strongly Correlated Electrons · Physics 2021-09-01 A. K. Zhuravlev

We propose a size-consistent generalization of the recently developed spin-extended configuration interaction with singles and doubles (ECISD), where a CI wave function is explicitly spin-projected. The size-consistent effect is effectively…

Chemical Physics · Physics 2017-01-25 Takashi Tsuchimochi , Seiichiro Ten-no