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We demonstrate that the Configuration Interaction (CI) Approximation recaptures essential features of the exact (Bethe Ansatz) solution to the 1D Hubbard model. As such, it provides valuable route for describing effects which go beyond…

Superconductivity · Physics 2009-10-31 Mona Berciu , Sajeev John

In this work we present the extension of semistochastic heat-bath configuration interaction (SHCI) to work with any two-component and four-component Hamiltonian. Vertical detachment energy (VDE) of AuH_2^- and zero-field splitting (ZFS) of…

Chemical Physics · Physics 2023-01-18 Xubo Wang , Sandeep Sharma

In this paper we use computer simulations to examine point defects in systems of "soft" colloidal particles including Hertzian spheres, and star polymers. We use Monte Carlo simulations to determine the deformation of the different crystals…

Soft Condensed Matter · Physics 2021-04-15 Marjolein de Jager , Joris de Jong , Laura Filion

This work deals with the efficient numerical solution of the time-fractional heat equation discretized on non-uniform temporal meshes. Non-uniform grids are essential to capture the singularities of "typical" solutions of time-fractional…

Numerical Analysis · Mathematics 2020-05-08 Xiaozhe Hu , Carmen Rodrigo , Francisco J. Gaspar

The efficiency of the recently proposed iCIPT2 [iterative configuration interaction (iCI) with selection and second-order perturbation theory (PT2); J. Chem. Theory Comput. 16, 2296 (2020)] for strongly correlated electrons is further…

Chemical Physics · Physics 2020-11-19 Ning Zhang , Wenjian Liu , Mark R. Hoffmann

Quantum algorithms for selecting a subspace of Hamiltonians to diagonalize have emerged as a promising alternative to variational algorithms in the NISQ era. So far, such algorithms, which include the quantum selected configuration…

This paper addresses the overwhelming computational resources needed with standard numerical approaches to simulate architected materials. Those multiscale heterogeneous lattice structures gain intensive interest in conjunction with the…

Numerical Analysis · Mathematics 2023-08-23 Thibaut Hirschler , Robin Bouclier , Pablo Antolin , Annalisa Buffa

We present the scheme that allows for efficient calculations of forces in the framework of pseudopotential self-interaction corrected (pSIC) formulation of the density functional theory. The scheme works with norm conserving and also with…

Strongly Correlated Electrons · Physics 2015-06-03 Malgorzata Wierzbowska , Jacek A. Majewski

A very accurate, (HF)$_2$ potential energy surface (PES) is constructed based on \ai\ calculations performed using the MOLPRO package at the CCSD(T) level of theory with an aug-cc-pvQz-F12 basis set at about 161~000 points. a higher…

Atomic and Molecular Clusters · Physics 2021-07-27 Roman I. Ovsyannikov , Vladimir Yu. Makhnev , Nikolai F. Zobov , Jacek Koput , Jonathan Tennyson

A one-electron Schroedinger equation based on special one-electron potentials for atoms is shown to exist that produces orbitals for an arbitrary molecule that are sufficiently accurate to be used without modification to construct single-…

Chemical Physics · Physics 2022-05-16 Jerry L. Whitten

While configuration interaction singles (CIS) provides a computationally efficient description of excited states, it systematically overestimates excitation energies and performs poorly for strongly correlated systems, partly due to the…

Chemical Physics · Physics 2026-04-01 Takashi Tsuchimochi , Benjamin Mokhtar

We have developed an application for studying heavy ion fusion barrier characteristics such as such as fusion barrier heights ($V_B$), positions ($R_B$) and curvature of the inverted parabola ($\hbar\omega$). We call this application as…

Nuclear Theory · Physics 2025-06-18 H. C. Manjunatha , P. S. Damodara Gupta , N. Sowmya , K. N. Sridhar

We study numerically classical 1-dimensional Hamiltonian lattices involving inter-particle long range interactions that decay with distance like 1/r^alpha, for alpha>=0. We demonstrate that although such systems are generally characterized…

Chaotic Dynamics · Physics 2015-09-01 Helen Christodoulidi , Tassos Bountis , Lambros Drossos

This paper proposes a novel optimization framework for discrete phase shifts of a reconfigurable intelligent surface (RIS) using a coherent Ising machine (CIM). Unlike conventional methods based on iterative convex approximation or…

Information Theory · Computer Science 2026-04-01 Yuto Hama , Daisuke Kitayama , Kensuke Inaba , Toshimori Honjo , Hiroki Takesue , Naoki Ishikawa , Hiroyuki Takahashi

We have developed and implemented a new quantum molecular dynamics approximation that allows fast and accurate simulations of dense plasmas from cold to hot conditions. The method is based on a carefully designed orbital-free implementation…

Plasma Physics · Physics 2015-06-22 Travis Sjostrom , Jerome Daligault

Self-consistent approaches to superfluid many-fermion systems in 3-dimensions (and subsequent time-dependent approaches) require a large number of diagonalizations of very large dimension hermitian matrices, which results in enormous…

Nuclear Theory · Physics 2017-04-12 Shi Jin , Aurel Bulgac , Kenneth Roche , Gabriel Wlazłowski

In this paper, we propose closed-form precoding schemes with optimal performance for constructive interference (CI) exploitation in the multiuser multiple-input single-output (MU-MISO) downlink. We first consider an optimization where we…

Information Theory · Computer Science 2017-12-22 Ang Li , Christos Masouros

The self-consistent theory of the correlation effects in Highly Correlated Systems(HCS) is presented. The novel Irreducible Green's Functions(IGF) method is discused in detail for the Hubbard model and random Hubbard model. The…

Strongly Correlated Electrons · Physics 2008-02-03 A. L. Kuzemsky

In this technical report we derive the analytic form of the Hessian matrix for shape matching energy. Shape matching is a useful technique for meshless deformation, which can be easily combined with multiple techniques in real-time…

Graphics · Computer Science 2020-03-17 Yun Fei

Fluid-Structure Interaction (FSI) can be investigated by means of non-linear Finite Element Models (FEM), suitable to capture large deflections of structural parts interacting with fluids, and Computational Fluid Dynamics (CFD). High…