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The Discontinuous Galerkin (DG) electronic structure method employs an adaptive local basis (ALB) set to solve the Kohn-Sham equations of density functional theory (DFT) in a discontinuous Galerkin framework. The adaptive local basis is…

Computational Physics · Physics 2016-10-19 Amartya S. Banerjee , Lin Lin , Wei Hu , Chao Yang , John E. Pask

We propose a new smoothing method for obtaining surface densities from discrete particle positions from numerical simulations. This is an essential step for many applications in gravitational lensing. This method is based on the ``scatter''…

Astrophysics · Physics 2011-02-11 Guo-Liang Li , S. Mao , Y. P. Jing , X. Kang , M. Bartelmann

We develop a general framework to calculate the many-body density of states (DOS) of isolated and interacting quantum systems. Based on the generalized coherent state formalism and the Simon-Lieb bounds for a quantum partition function, our…

Strongly Correlated Electrons · Physics 2026-04-17 Deniz Coskun , R. Chitra

We propose a method to probe the local density of states (LDOS) of atomic systems that provides both spatial and energy resolution. The method combines atomic and tunneling techniques to supply a simple, yet quantitative and operational,…

Mesoscale and Nanoscale Physics · Physics 2018-11-22 Daniel Gruss , Chih-Chun Chien , Julio Barreiro , Massimiliano Di Ventra , Michael Zwolak

We consider a generalisation of Ulam's method for approximating invariant densities of one-dimensional chaotic maps. Rather than use piecewise constant polynomials to approximate the density, we use polynomials of degree n which are defined…

Numerical Analysis · Mathematics 2011-11-28 Philip J. Aston , Oliver Junge

We report an efficient quantum algorithm for estimating the local density of states (LDOS) on a quantum computer. The LDOS describes the redistribution of energy levels of a quantum system under the influence of a perturbation. Sometimes…

Quantum Physics · Physics 2009-11-10 Joseph Emerson , Seth Lloyd , David Poulin , David Cory

Starting from the observation that one of the most successful methods for solving the Kohn-Sham equations for periodic systems -- the plane-wave method -- is a spectral method based on eigenfunction expansion, we formulate a spectral method…

Computational Physics · Physics 2016-03-08 Amartya S. Banerjee , Ryan S. Elliott , Richard D. James

Perturbation theory is a powerful tool for studying large-scale structure formation in the universe and calculating observables such as the power spectrum or bispectrum. However, beyond linear order, typically this is done by assuming a…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-09 Nicholas Choustikov , Zvonimir Vlah , Anthony Challinor

Hidden Markov Models (HMMs) can be accurately approximated using co-occurrence frequencies of pairs and triples of observations by using a fast spectral method in contrast to the usual slow methods like EM or Gibbs sampling. We provide a…

Machine Learning · Statistics 2012-03-29 Dean P. Foster , Jordan Rodu , Lyle H. Ungar

We present a new supervised deep-learning approach to the problem of the extraction of smeared spectral densities from Euclidean lattice correlators. A distinctive feature of our method is a model-independent training strategy that we…

High Energy Physics - Lattice · Physics 2024-01-08 Michele Buzzicotti , Alessandro De Santis , Nazario Tantalo

By analyzing the global density of states (DOS) in the Double-Scaled Sachdev-Ye-Kitaev (DSSYK) model, we construct a finite-dimensional Hamiltonian that replicates this DOS. We then tridiagonalize the Hamiltonian to determine the mean…

High Energy Physics - Theory · Physics 2025-01-16 Pratik Nandy

Recently, sparsity-based algorithms are proposed for super-resolution spectrum estimation. However, to achieve adequately high resolution in real-world signal analysis, the dictionary atoms have to be close to each other in frequency,…

Machine Learning · Statistics 2015-06-05 Yiyuan She , Huanghuang Li , Jiangping Wang , Dapeng Wu

Trace estimators allow to approximate thermodynamic equilibrium observables with astonishing accuracy. A prominent representative is the finite-temperature Lanczos method (FTLM) which relies on a Krylov space expansion of the exponential…

Strongly Correlated Electrons · Physics 2021-12-07 H. Schlüter , F. Gayk , H. -J. Schmidt , A. Honecker , J. Schnack

The local density of states (LDOS) in finite quantum wires is calculated as a function of discrete energies and position along the wire. By using a combination of numerical density matrix renormalization group (DMRG) calculations and…

Strongly Correlated Electrons · Physics 2009-11-13 Imke Schneider , Alexander Struck , Michael Bortz , Sebastian Eggert

} The main goal of this note is to provide new, mostly multidimensional densities, compactly supported and list many of its properties that enable effective calculations. The idea of obtaining such densities is firstly to build some…

Classical Analysis and ODEs · Mathematics 2018-08-08 Paweł J. Szabłowski

We introduce a novel conditional density estimation model termed the conditional density operator (CDO). It naturally captures multivariate, multimodal output densities and shows performance that is competitive with recent neural…

Machine Learning · Computer Science 2019-10-30 Ingmar Schuster , Mattes Mollenhauer , Stefan Klus , Krikamol Muandet

We present a real-space spectral method for computing the orbital magnetization of crystals. Starting from the commutator form of the orbital magnetization operator, we formulate an energy-resolved spectral function that is amenable to…

We introduce a generalization of local density of states which is "windowed" with respect to position and energy, called the windowed local density of states (wLDOS). This definition generalizes the usual LDOS in the sense that the usual…

Mathematical Physics · Physics 2022-10-25 Terry A. Loring , Jianfeng Lu , Alexander B. Watson

In the present work, we investigate the computational efficiency afforded by higher-order finite-element discretization of the saddle-point formulation of orbital-free density functional theory. We first investigate the robustness of viable…

Computational Physics · Physics 2015-05-30 Phani Motamarri , Mrinal Iyer , Jaroslaw Knap , Vikram Gavini

We propose the ultra-fast numerical approach to large-scale inhomogeneous superconductors, which we call the Localized Krylov Bogoliubov-de Gennes method (LK-BdG). In the LK-BdG method, the computational complexity of the local Green's…

Superconductivity · Physics 2020-06-30 Yuki Nagai