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A variational method is discussed, extending the Gaussian effective potential to higher orders. The single variational parameter is replaced by trial unknown two-point functions, with infinite variational parameters to be optimized by the…

High Energy Physics - Phenomenology · Physics 2013-09-30 Fabio Siringo

A new diagrammatic technique is developed to describe nonlocal effects (e.g., pseudogap formation) in the Hubbard-like models. In contrast to cluster approaches, this method utilizes an exact transition to the dual set of variables, and it…

Strongly Correlated Electrons · Physics 2007-05-23 A. N. Rubtsov , M. I. Katsnelson , A. I. Lichtenstein

We present a swift walk-through of our recent work that uses machine learning to fit interatomic potentials based on quantum mechanical data. We describe our Gaussian Approximation Potentials (GAP) framework, discussing a variety of…

Materials Science · Physics 2020-02-06 Albert P. Bartók , Gábor Csányi

A method is developed for generating pseudopotentials for use in correlated-electron calculations. The paradigms of shape and energy consistency are combined and defined in terms of correlated-electron wave-functions. The resulting energy…

Materials Science · Physics 2017-05-26 John R. Trail , Richard J. Needs

The Gaussian process (GP) regression model is a widely employed surrogate modeling technique for computer experiments, offering precise predictions and statistical inference for the computer simulators that generate experimental data.…

Methodology · Statistics 2024-04-02 Lulu Kang , Yuanxing Cheng , Yiwei Wang , Chun Liu

We show that the Gaussian Approximation Potential machine learning framework can describe complex magnetic potential energy surfaces, taking ferromagnetic iron as a paradigmatic challenging case. The training database includes total…

Materials Science · Physics 2018-02-07 Daniele Dragoni , Thomas D. Daff , Gabor Csanyi , Nicola Marzari

Antiferromagnetic and charge ordered Hartree-Fock solutions of the one-band Hubbard model with on-site and nearest-neighbor Coulomb repulsions are exactly mapped onto an auxiliary local Kohn-Sham (KS) problem within a density-functional…

Strongly Correlated Electrons · Physics 2007-05-23 I. V. Solovyev

This work aims to model the hypersurface of the effective elastic modulus, \( E_{z, \text{eff}} \), and thickness, \( th_{\text{eff}} \), in corrugated boards. A Latin Hypercube Sampling (LHS) is followed by Gaussian Process Regression…

Applied Physics · Physics 2025-07-04 Ricardo Fitas

The repulsive Hubbard Hamiltonian is one of the foundational models describing strongly correlated electrons and is believed to capture essential aspects of high temperature superconductivity. Ultracold fermions in optical lattices allow…

Collective electronic fluctuations in correlated materials give rise to various important phenomena, such as existence of the charge ordering, superconductivity, Mott insulating and magnetic phases, plasmon and magnon modes, and other…

Strongly Correlated Electrons · Physics 2019-03-19 E. A. Stepanov , A. Huber , A. I. Lichtenstein , M. I. Katsnelson

An effective-medium theory (EMT) is developed to predict the effective permittivity \epsilon_eff of dense random dispersions of high optical-conductivity metals such as Ag, Au and Cu. Dependence of \epsilon_eff on the volume fraction \phi,…

Materials Science · Physics 2015-06-04 Satvik N. Wani , Ashok S. Sangani , Radhakrishna Sureshkumar

We present a high-accuracy procedure for electronic structure calculations of strongly correlated materials. To address limitations in current electronic structure methods, we employ density functional theory in combination with the…

Correlation effects play an important role in the electronic structure of half-metallic (HM) magnets. In particular, they give rise to non-quasiparticle states above (or below) the Fermi energy at finite temperatures that reduce the spin…

Strongly Correlated Electrons · Physics 2015-06-17 Ersoy Sasioglu , Iosif Galanakis , Christoph Friedrich , Stefan Blügel

Effective range is a quantity to characterize the energy dependence in two-body scattering strength, and is widely used in cold atomic systems especially across narrow resonances. Here we show that the effective range can significantly…

Quantum Gases · Physics 2019-01-16 Lei Pan , Xiaoling Cui , Shu Chen

In the present work, a relation has been established between degree of polarization and effective mass ratio (EMR) and magnetoresistance (MR) of one-dimensional non-degenerate system (which can represent a nano-wire or a linear chain of…

Strongly Correlated Electrons · Physics 2008-06-20 Piyush Dua

A non-perturbative effective model is derived for the Higgs sector of the standard model, described by a simple scalar theory. The renormalized couplings are determined by the derivatives of the Gaussian Effective Potential that are known…

High Energy Physics - Phenomenology · Physics 2011-01-04 Fabio Siringo , Luca Marotta

A challenge - and opportunity - is offered to the Hubbard Model community of solutions extant for the strong coupling region. A rigorous and quantitatively demanding test - a Computer Lab - is presented based on certain exact results for…

Strongly Correlated Electrons · Physics 2018-12-11 Donald M. Esterling

A strong-coupling expansion for models of correlated electrons in any dimension is presented. The method is applied to the Hubbard model in $d$ dimensions and compared with numerical results in $d=1$. Third order expansion of the Green…

Strongly Correlated Electrons · Physics 2009-10-30 Stéphane Pairault , David Sénéchal , A. -M. S. Tremblay

Gaussian Approximation Potentials are a class of Machine Learned Interatomic Potentials routinely used to model materials and molecular systems on the atomic scale. The software implementation provides the means for both fitting models…

A multi-band effective-mass Hamiltonian is derived for lattice-matched semiconductor nanostructures in a slowly varying external magnetic field. The theory is derived from the first-principles magnetic-field coupling Hamiltonian of Pickard…

Materials Science · Physics 2007-05-23 Bradley A. Foreman