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Radiative corrections to an atom are calculated near a half-space that has arbitrarily-shaped small depositions upon its surface. The method is based on calculation of the classical Green's function of the macroscopic Maxwell equations near…

Quantum Physics · Physics 2015-08-19 Robert Bennett

We consider a compression method for boundary element matrices arising in the context of the computation of electrostatic fields. Green cross approximation combines an analytic approximation of the kernel function based on Green's…

Numerical Analysis · Mathematics 2018-10-22 Steffen Börm , Sven Christophersen

We propose the regularized compressed double factorization (RC-DF) method to classically compute compressed representations of molecular Hamiltonians that enable efficient simulation with noisy intermediate scale (NISQ) and error corrected…

Significant effort in applied quantum computing has been devoted to the problem of ground state energy estimation for molecules and materials. Yet, for many applications of practical value, additional properties of the ground state must be…

Quantum Physics · Physics 2022-07-13 Ruizhe Zhang , Guoming Wang , Peter Johnson

We leverage powerful mathematical tools stemming from optimal transport theory and transform them into an efficient algorithm to reconstruct the fluctuations of the primordial density field, built on solving the Monge-Amp\`ere-Kantorovich…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-14 Bruno Lévy , Roya Mohayaee , Sebastian von Hausegger

We introduce the Green's functions technique as an alternative theory to the quantum regression theorem formalism for calculating the two-time correlation functions in open quantum systems. In particular, we investigate the potential of…

Quantum Physics · Physics 2015-02-03 Edgar A. Gomez , J. D. Hernandez-Rivero , Herbert Vinck-Posada

This review deals with the nonequilibrium Green's function (NEGF) method applied to the problems of energy transport due to atomic vibrations (phonons), primarily for small junction systems. We present a pedagogical introduction to the…

Mesoscale and Nanoscale Physics · Physics 2013-05-28 Jian-Sheng Wang , Bijay Kumar Agarwalla , Huanan Li , Juzar Thingna

We develop a second order correction to commonly used density functional approximations (DFA) to eliminate the systematic delocalization error. The method, based on the previously developed global scaling correction (GSC), is an exact…

Chemical Physics · Physics 2021-07-22 Yuncai Mei , Zehua Chen , Weitao Yang

With the aim of establishing a framework to efficiently perform the practical application of quantum chemistry simulation on near-term quantum devices, we envision a hybrid quantum--classical framework for leveraging problem decomposition…

We present novel methods implemented within the non-equilibrium Green function code (NEGF) transiesta based on density functional theory (DFT). Our flexible, next-generation DFT-NEGF code handles devices with one or multiple electrodes…

Mesoscale and Nanoscale Physics · Physics 2016-12-30 Nick Papior , Nicolás Lorente , Thomas Frederiksen , Alberto García , Mads Brandbyge

We implement an adaptation of the COLA approach, a hybrid scheme that combines Lagrangian perturbation theory with an N-body approach, to model non-linear collapse in chameleon and symmetron modified gravity models. Gravitational screening…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-30 Georgios Valogiannis , Rachel Bean

Inhomogeneous dynamical mean-field theory has been employed to solve many interesting strongly interacting problems from transport in multilayered devices to the properties of ultracold atoms in a trap. The main computational step,…

Strongly Correlated Electrons · Physics 2011-02-17 Pierre Carrier , Jok M. Tang , Yousef Saad , James K. Freericks

The construction of the Hamiltonian matrix \textbf{H} is an essential, yet computationally expensive step in \textit{ab-initio} device simulations based on density-functional theory (DFT). In homogeneous structures, the fact that a unit…

Disordered Systems and Neural Networks · Physics 2026-02-03 Chen Hao Xia , Manasa Kaniselvan , Marko Mladenoivić , Mathieu Luisier

Modeling quantum many-body systems is enormously challenging due to the exponential scaling of Hilbert dimension with system size. Finding efficient compressions of the wavefunction is key to building scalable models. Here, we introduce…

Computational Physics · Physics 2020-03-16 Christopher Roth

The multigroup neutron transport criticality calculations using modern supercomputers have been widely employed in a nuclear reactor analysis for studying whether or not a system is self-sustaining. However, the design and development of…

Numerical Analysis · Mathematics 2020-02-19 Fande Kong

We describe microscopic theory for the quantum transport through finite interacting systems connected to noninteracting leads. It can be applied to small systems such as quantum dots, quantum wires, atomic chain, molecule, and so forth. The…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Akira Oguri

Driven by Moore's Law, the dimensions of transistors have been pushed down to the nanometer scale. Advanced quantum transport (QT) solvers are required to accurately simulate such nano-devices. The non-equilibrium Green's function (NEGF)…

Distributed, Parallel, and Cluster Computing · Computer Science 2026-01-09 Vincent Maillou , Matthias Bollhofer , Olaf Schenk , Alexandros Nikolaos Ziogas , Mathieu Luisier

Gradient descent algorithms on Riemannian manifolds have been used recently for the optimization of quantum channels. In this contribution, we investigate the influence of various regularization terms added to the cost function of these…

Quantum Physics · Physics 2024-05-01 Felix Soest , Konstantin Beyer , Walter T. Strunz

This study presents a simulation approach for three-dimensional nanotube networks using cubic and tetragonal unit cells to enhance modeling efficiency. A random-walk algorithm was developed to generate these networks, which were analyzed in…

Computational Physics · Physics 2025-01-29 Fabian Gumpert , Dominik Eitel , Olaf Kottas , Uta Helbig , Jan Lohbreier

We present a recently-developed renormalization group scheme, the functional renormalization group (fRG), as a many-particle method suited to account for the two-particle interactions between the electrons in complex quantum dot geometries.…

Strongly Correlated Electrons · Physics 2007-05-23 C. Karrasch