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The minimization of the loss function is of paramount importance in deep neural networks. On the other hand, many popular optimization algorithms have been shown to correspond to some evolution equation of gradient flow type. Inspired by…

Machine Learning · Computer Science 2020-02-24 Imen Ayadi , Gabriel Turinici

In the graph-based semi-supervised learning, the Green-function method is a classical method that works by computing the Green's function in the graph space. However, when applied to large graphs, especially those sparse ones, this method…

Machine Learning · Computer Science 2024-11-05 Feiping Nie , Yitao Song , Wei Chang , Rong Wang , Xuelong Li

On the basis of spin and pairing fluctuation-exchange approximation, we study the superconductivity in quasi-two-dimensional Hubbard model. The integral equations for the Green's function are self-consistently solved by numerical…

Superconductivity · Physics 2009-10-23 Xin-Zhong Yan

Gaussian processes (GPs) are a good choice for function approximation as they are flexible, robust to over-fitting, and provide well-calibrated predictive uncertainty. Deep Gaussian processes (DGPs) are multi-layer generalisations of GPs,…

Machine Learning · Statistics 2017-11-15 Hugh Salimbeni , Marc Deisenroth

We apply a stochastic resolution of identity approximation (sRI) to the CC2 method for excitation energy calculations. A set of stochastic orbitals are employed to decouple the crucial 4-index electron repulsion integrals and optimize the…

Chemical Physics · Physics 2023-10-31 Chongxiao Zhao , Qi Ou , Joonho Lee , Wenjie Dou

We present a data-driven approach to mathematically model physical systems whose governing partial differential equations are unknown, by learning their associated Green's function. The subject systems are observed by collecting…

Numerical Analysis · Mathematics 2023-03-13 Harshwardhan Praveen , Nicolas Boulle , Christopher Earls

A stochastic iterative algorithm approximating second-order information using von Neumann series is discussed. We present convergence guarantees for strongly-convex and smooth functions. Our analysis is much simpler in contrast to a similar…

Optimization and Control · Mathematics 2017-04-14 Mojmir Mutny

We present a complete prescription for the numerical calculation of surface Green's functions and self-energies of semi-infinite quasi-onedimensional systems. Our work extends the results of Sanvito et al. [1] generating a robust algorithm…

Materials Science · Physics 2007-12-11 Ivan Rungger , Stefano Sanvito

In a recent publication (Phys. Rev E 77, 056705 (2008)),we have presented the stochastic Green function (SGF) algorithm, which has the properties of being general and easy to apply to any lattice Hamiltonian of the form H=V-T, where V is…

Statistical Mechanics · Physics 2008-11-24 V. G. Rousseau

A method of the self-consistent calculation of the thermodynamical and correlation functions is presented. This approach is based on the GRPA (generalized random phase approximation) scheme with the inclusion of the mean field corrections.…

Superconductivity · Physics 2016-08-31 I. V. Stasyuk , A. M. Shvaika , K. V. Tabunshchyk

We introduce an efficient and accurate staggered-grid finite-difference (SGFD) method to solve the two-dimensional elastic wave equation. We use a coupled first-order stress-velocity formulation. In the standard implementation of SGFD…

Numerical Analysis · Mathematics 2020-12-15 Wenquan Liang , Yanfei Wang , Ursula Iturrarán-Viveros

A two-stage multi-period mixed-integer linear stochastic programming model is proposed to assist qualified operators in long-term generation and transmission expansion planning of electricity and gas systems to meet policy objectives. The…

Optimization and Control · Mathematics 2025-05-22 Giovanni Micheli , Maria Teresa Vespucci , Alessia Cortazzi , Cinzia Puglisi

The Green's function method in the \emph{Quasiparticle Time Blocking Approximation} is applied to nuclear excitations in $^{132}$Sn and $^{208}$Pb. The calculations are performed self-consistently using a Skyrme interaction. The method…

Nuclear Theory · Physics 2008-11-26 N. Lyutorovich , J. Speth , A. Avdeenkov , F. Gruemmer , S. Kamerdzhiev , S. Krewald , V. I. Tselyaev

Following early work on Hessian-free methods for deep learning, we study a stochastic generalized Gauss-Newton method (SGN) for training DNNs. SGN is a second-order optimization method, with efficient iterations, that we demonstrate to…

Machine Learning · Computer Science 2020-06-11 Matilde Gargiani , Andrea Zanelli , Moritz Diehl , Frank Hutter

Green's function provides an inherent connection between theoretical analysis and numerical methods for elliptic partial differential equations, and general absence of its closed-form expression necessitates surrogate modeling to guide the…

Numerical Analysis · Mathematics 2025-09-16 Qi Sun , Shengyan Li , Bowen Zheng , Lili Ju , Xuejun Xu

Within many-body perturbation theory, Hedin's formalism offers a systematic way to iteratively compute the self-energy $\Sigma$ of any interacting system, provided one can evaluate the interaction vertex $\Gamma$ exactly. This is however…

Chemical Physics · Physics 2022-11-04 Carlos Mejuto-Zaera , Vojtěch Vlček

We present a nontrivial model system of interacting electrons that can be solved analytically in the GW approximation. We obtain the particle number from the GW Green's function strictly analytically, and prove that there is a genuine…

Materials Science · Physics 2008-02-03 Arno Schindlmayr

The self-energy functional theory (SFT) is generalized to describe the real-time dynamics of correlated lattice-fermion models far from thermal equilibrium. This is achieved by means of a reformulation of the original equilibrium theory in…

Strongly Correlated Electrons · Physics 2013-10-21 Felix Hofmann , Martin Eckstein , Enrico Arrigoni , Michael Potthoff

The self-consistent Gaussian approximation (SCGA) for classical spin systems described by a completely anisotropic D-component vector model is proposed, which takes into account fluctuations of the molecular field and thus is a next step…

Statistical Mechanics · Physics 2009-10-31 D. A. Garanin

Quasiparticle (QP) excitations are extremely important for understanding and predicting charge transfer and transport in molecules, nanostructures and extended systems. Since density functional theory (DFT) within the Kohn-Sham (KS)…

Chemical Physics · Physics 2017-07-18 Vojtech Vlcek , Eran Rabani , Daniel Neuhauser , Roi Baer