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We review the problem of how to compute the spectral density of sparse symmetric random matrices, i.e. weighted adjacency matrices of undirected graphs. Starting from the Edwards-Jones formula, we illustrate the milestones of this line of…

Statistical Mechanics · Physics 2021-08-11 Vito A R Susca , Pierpaolo Vivo , Reimer Kühn

The Grassmann manifold of linear subspaces is important for the mathematical modelling of a multitude of applications, ranging from problems in machine learning, computer vision and image processing to low-rank matrix optimization problems,…

Numerical Analysis · Mathematics 2024-01-09 Thomas Bendokat , Ralf Zimmermann , P. -A. Absil

We present a Riemannian optimization framework for Hartree-Fock theory formulated directly in the Sobolev space $H^1$. The orthonormality constraints are interpreted geometrically via infinite-dimensional Stiefel and Grassmann manifolds…

Quantum Physics · Physics 2026-03-18 Evgueni Dinvay

A numerical method is presented for reproducing fermionic quantum gas microscope experiments in equilibrium. By employing nested componentwise direct sampling of fermion pseudo-density matrices, as they arise naturally in determinantal…

Quantum Gases · Physics 2021-08-31 Stephan Humeniuk , Yuan Wan

The self-consistent field method utilized for solving the Hartree-Fock (HF) problem and the closely related Kohn-Sham problem, is typically thought of as one of the cheapest methods available to quantum chemists. This intuition has been…

Quantum Physics · Physics 2015-06-22 James D. Whitfield , Zoltán Zimborás

This article addresses a fundamental problem faced by the ab initio community: the lack of an effective formalism for the rapid exploration and exchange of new methods. To rectify this, we introduce a novel, basis-set independent,…

Materials Science · Physics 2009-10-31 Sohrab Ismail-Beigi , T. A. Arias

In recent years, methods of approximate parameter estimation have attracted considerable interest in complex problems where exact likelihoods are hard to obtain. In their most basic form, Bayesian methods such as Approximate Bayesian…

Computation · Statistics 2015-07-17 Johanna Bertl , Gregory Ewing , Carolin Kosiol , Andreas Futschik

Self-consistent field theory (SCFT) is one of the most widely-used framework in studying the equilibrium phase behaviors of inhomogenous polymers. For liquid crystalline polymeric systems, the main numerical challenges of solving SCFT…

Numerical Analysis · Mathematics 2024-09-16 Zhijuan He , Kai Jiang , Liwei Tan , Xin Wang

We present a density matrix approach for computing global solutions of Hartree-Fock theory, based on semidefinite programming (SDP), that gives upper and lower bounds on the Hartree-Fock energy of quantum systems. Equality of the upper- and…

Chemical Physics · Physics 2014-02-11 Srikant Veeraraghavan , David A. Mazziotti

A new numerical method for the solution of the Dynamical Mean Field Theory's self-consistent equations is introduced. The method uses the Density Matrix Renormalization Group technique to solve the associated impurity problem. The new…

Strongly Correlated Electrons · Physics 2016-08-31 Daniel J. Garcia , Karen Hallberg , Marcelo J. Rozenberg

We present a systematic Density Functional Theory (DFT) study of geometries and energies of the nucleic acid DNA bases (guanine, adenine, cytosine and thymine) and 30 different DNA base-pairs. We use a recently developed linear-scaling DFT…

Chemical Physics · Physics 2007-05-23 Maider Machado , Pablo Ordejon , Emilio Artacho , Daniel Sanchez-Portal , Jose M. Soler

Traditional problems in computational geometry involve aspects that are both discrete and continuous. One such example is nearest-neighbor searching, where the input is discrete, but the result depends on distances, which vary continuously.…

Computational Geometry · Computer Science 2023-08-21 Ahmed Abdelkader , David M. Mount

Given a Hamiltonian with a continuous symmetry one can generally factorize that symmetry and consider the dynamics on invariant Hilbert Spaces. In Statistical Mechanics this procedure is known as the vertex-IRF map, and in certain cases,…

Statistical Mechanics · Physics 2009-10-28 G. Sierra , T. Nishino

This paper initiates a systematic development of a theory of non-commutative optimization. It aims to unify and generalize a growing body of work from the past few years which developed and analyzed algorithms for natural geodesically…

Optimization and Control · Mathematics 2021-07-28 Peter Bürgisser , Cole Franks , Ankit Garg , Rafael Oliveira , Michael Walter , Avi Wigderson

Persistent homology is a topological feature used in a variety of applications such as generating features for data analysis and penalizing optimization problems. We develop an approach to accelerate persistent homology computations…

Algebraic Topology · Mathematics 2023-01-19 Yuan Luo , Bradley J. Nelson

Our research objective in this paper is to reconstruct an initial linear density field, which follows the multivariate Gaussian distribution with variances given by the linear power spectrum of the current CDM model and evolves through…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Huiyuan Wang , H. J. Mo , Xiaohu Yang , Frank C. van den Bosch

Large-scale applications of energy density functional (EDF) methods depend on fast and reliable algorithms to solve the associated non-linear self-consistency problem. When dealing with large single-particle variational spaces, existing…

Nuclear Theory · Physics 2019-06-24 W. Ryssens , M. Bender , P. -H. Heenen

We consider the problem of sampling from posterior distributions for Bayesian models where some parameters are restricted to be orthogonal matrices. Such matrices are sometimes used in neural networks models for reasons of regularization…

Machine Learning · Statistics 2019-01-24 Viktor Yanush , Dmitry Kropotov

We discuss a test of a recently proposed approach to determine average pairing matrix elements within a given interval of single-particle states (sp) around the Fermi level $\lambda$ as obtained in the so-called uniform gap method (UGM). It…

Nuclear Theory · Physics 2024-09-18 T. V. Nhan Hao , N. N. Bao Nguyen , D. Quang Tam , P. Quentin , Meng-Hock Koh , L. Bonneau

A new decomposition of the Dirac structure of nucleon self-energies in the Dirac Brueckner-Hartree-Fock (DBHF) approach is adopted to investigate the equation of state for asymmetric nuclear matter. The effective coupling constants of…

Nuclear Theory · Physics 2009-11-07 Zhong-yu Ma , Ling Liu