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We derive a relation between four-fermion QED Green functions of different covariant gauges which defines the gauge dependence completely. We use the derived gauge dependence to check the gauge invariance of atom-like bound state…

High Energy Physics - Phenomenology · Physics 2009-10-28 Grigirii Pivovarov

We provide an in-depth examination of the $GW$ approximation of Green's function many-body perturbation theory by detailing both its theoretical and practical aspects in the realm of quantum chemistry. First, the quasiparticle context is…

Chemical Physics · Physics 2024-03-20 Antoine Marie , Abdallah Ammar , Pierre-François Loos

In this study, we introduce a novel approach to coupled-cluster Green's function (CCGF) embedding by seamlessly integrating conventional CCGF theory with the state-of-the-art sub-system embedding sub-algebras coupled cluster (SES-CC)…

Quantum Physics · Physics 2023-12-21 Bo Peng , Karol Kowalski

The exact Green function is constructed for a quantum system, with known Green function, which is decorated by two delta function impurities.It is shown that when two such impurities coincide they behave as a single singular potential with…

Quantum Physics · Physics 2017-02-20 M. L. Glasser

Density matrix embedding theory (DMET) [Phys. Rev. Lett., 109, 186404 (2012)], introduced a new approach to quantum cluster embedding methods, whereby the mapping of strongly correlated bulk problems to an impurity with finite set of bath…

Strongly Correlated Electrons · Physics 2015-06-24 George H. Booth , Garnet Kin-Lic Chan

Quantum embedding theories are promising approaches to investigate strongly-correlated electronic states of active regions of large-scale molecular or condensed systems. Notable examples are spin defects in semiconductors and insulators. We…

Materials Science · Physics 2021-12-14 He Ma , Nan Sheng , Marco Govoni , Giulia Galli

A reformulation of site-occupation embedding theory (SOET) in terms of Green's functions is presented. Referred to as site-occupation--Green's function embedding theory (SOGET), this novel extension of density-functional theory for model…

Strongly Correlated Electrons · Physics 2019-11-07 Laurent Mazouin , Matthieu Saubanère , Emmanuel Fromager

The accurate theoretical description of materials with strongly correlated electrons is a formidable challenge in condensed matter physics and computational chemistry. Dynamical Mean Field Theory (DMFT) is a successful approach that…

We derive a relation between four-fermion QED Green functions of different covariant gauges which defines the gauge dependence completely. We use the derived gauge dependence to check the gauge invariance of atom-like bound state…

High Energy Physics - Phenomenology · Physics 2016-09-01 Grigorii B. Pivovarov

We present an efficient implementation of a surface Green's-function method for atomistic modeling of surfaces within the framework of density functional theory using a pseudopotential localized basis set approach. In this method, the…

We develop a Green's function approach to quasiparticle excitations of open-shell systems within the GW approximation. It is shown that accurate calculations of the characteristic multiplet structure require a precise knowledge of the self…

Materials Science · Physics 2014-09-11 Johannes Lischner , Jack Deslippe , Manish Jain , Steven G. Louie

Precise predictions of atomic energy levels require the use of QED, especially in highly-charged ions, where the inner electrons have relativistic velocities. We present an overview of the two-time Green's function method; this method…

Atomic Physics · Physics 2007-05-23 E. -O. Le Bigot , P. Indelicato , V. M. Shabaev

Gauge invariant quark two-point Green's functions defined with path-ordered gluon field phase factors along skew-polygonal lines joining the quark to the antiquark are considered. Functional relations between Green's functions with…

High Energy Physics - Phenomenology · Physics 2008-11-26 H. Sazdjian

An end-to-end strategy for hybrid quantum-classical computations of Green's functions in many-body systems is presented and applied to the pairing model. The scheme makes explicit use of the spectral representation of the Green's function,…

Nuclear Theory · Physics 2026-05-01 Samuel Aychet-Claisse , Denis Lacroix , Vittorio Somà , Jing Zhang

In this work we present a three step procedure for generating a closed form expression of the Green's function on both closed and open finite quantum graphs with general self-adjoint matching conditions. We first generalize and simplify the…

Quantum Physics · Physics 2023-09-21 Tristan Lawrie , Sven Gnutzmann , Gregor Tanner

Green's functions in Physics have proven to be a valuable tool for understanding fundamental concepts in different branches, such as electrodynamics, solid-state and many -body problems. In quantum mechanics advanced courses, Green's…

Physics Education · Physics 2022-10-05 William J. Herrera , Herbert Vinck-Posada , Shirley Gomez Paez

We revisit the volume Green's function integral equation for modelling light scattering with discretization strategies as well as numerical integration recipes borrowed from finite element method. The merits of introducing finite element…

Optics · Physics 2019-06-26 Wen Li , Dong Tan , Jing Xu , Shubo Wang , Yuntian Chen

Quantum computers hold promise to enable efficient simulations of the properties of molecules and materials; however, at present they only permit ab initio calculations of a few atoms, due to a limited number of qubits. In order to harness…

Materials Science · Physics 2020-07-07 He Ma , Marco Govoni , Giulia Galli

We present a novel scheme to the coverage problem, introducing a quantitative way to estimate the interaction between a block and its enviroment.This is achieved by setting a discrete version of Green`s theorem, specially adapted for Model…

Symbolic Computation · Computer Science 2007-05-23 Eli Appleboim , Emil Saucan

The gauge invariant quark Green's function, defined with a path-ordered phase factor along a straight line, is studied in two-dimensional QCD in the large-N_c limit by means of an exact integrodifferential equation. It is found to be…

High Energy Physics - Theory · Physics 2011-02-01 H. Sazdjian