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An algorithm, based on numerical description of the terms of many-body perturbation theory (Goldstone diagrams), is presented. The algorithm allows the use of the same piece of computer code to evaluate any particular diagram in any…

Atomic Physics · Physics 2015-05-13 V. A. Dzuba

We propose a simple linear scaling expression in reciprocal space for evaluating the ion--electron potential of crystalline solids. The expression replaces the long-range ion--electron potential with an equivalent localized charge…

Materials Science · Physics 2016-12-21 Xuecheng Shao , Wenhui Mi , Qiang Xu , Yanchao Wang , Yanming Ma

A direct integration algorithm is described to compute the magnetostatic field and energy for given magnetization distributions on not necessarily uniform tensor grids. We use an analytically-based tensor approximation approach for…

Computational Physics · Physics 2012-03-21 Lukas Exl , Winfried Auzinger , Simon Bance , Markus Gusenbauer , Franz Reichel , Thomas Schrefl

Numerical calculus algorithms which estimate derivatives and integrals from data series acquired either via measurements or by sampling functions are essential in scientific computing. To date, a few quantum algorithms have been developed…

Quantum Physics · Physics 2026-03-23 Jordan Cioni , Fabio Semperlotti

Electric field-assisted chemistry has attracted much attention in recent years, particularly in the context of oriented external electric fields for controlling molecular structure and reactivity. Such fields have been explored in a wide…

Chemical Physics · Physics 2026-05-08 Duc Anh Lai , Devin A. Matthews

Superlevel partitioning is combined with a simple relaxation procedure to construct an iterative technique for solving equations of statistical equilibrium. In treating an $N$-level model atom, the technique avoids the $N^{3}$ scaling in…

Astrophysics · Physics 2009-11-06 L. B. Lucy

We study gradient magnetometry with an ensemble of atoms with arbitrary spin. We calculate precision bounds for estimating the gradient of the magnetic field based on the quantum Fisher information. For quantum states that are invariant…

Quantum Physics · Physics 2018-06-08 Iagoba Apellaniz , Inigo Urizar-Lanz , Zoltan Zimboras , Philipp Hyllus , Geza Toth

This paper presents a statistical model for stationary ergodic point processes, estimated from a single realization observed in a square window. With existing approaches in stochastic geometry, it is very difficult to model processes with…

Machine Learning · Statistics 2022-09-16 Antoine Brochard , Bartłomiej Błaszczyszyn , Stéphane Mallat , Sixin Zhang

We propose a new algorithm for calculation of vibrational spectra of molecules using tensor train decomposition. Under the assumption that eigenfunctions lie on a low-parametric manifold of low-rank tensors we suggest using well-known…

Numerical Analysis · Mathematics 2016-10-12 Maxim Rakhuba , Ivan Oseledets

Electromagnetic fields are generated in high energy nuclear collisions by spectator valence protons. These fields are traditionally computed by integrating the Maxwell equations with point sources. One might expect that such an approach is…

High Energy Physics - Phenomenology · Physics 2016-12-21 Robert Holliday , Ryan McCarty , Balthazar Peroutka , Kirill Tuchin

Traditional methods in quantum chemistry rely on Hartree-Fock-based Slater-determinant (SD) representations, whose underlying zeroth-order picture assumes separability by particle. Here, we explore a radically different approach, based on…

Quantum Physics · Physics 2022-03-02 Bill Poirier , Jonathan Jerke

Finding gradients is a crucial step in training machine learning models. For quantum neural networks, computing gradients using the parameter-shift rule requires calculating the cost function twice for each adjustable parameter in the…

Quantum Physics · Physics 2025-01-31 Guang Ping He

Using trapped ions in an entangled state we propose detecting a magnetic dipole of a single atom at distance of a few $\mu$m. This requires a measurement of the magnetic field gradient at a level of about 10$^{-13}$ Tesla/$\mu$m. We discuss…

Quantum Physics · Physics 2015-06-05 F. Schmidt-Kaler , R. Gerritsma

We present an electron identification algorithm based on a neural network approach applied to the ZEUS uranium calorimeter. The study is motivated by the need to select deep inelastic, neutral current, electron proton interactions…

High Energy Physics - Experiment · Physics 2010-11-01 H. Abramowicz , A. Caldwell , R. Sinkus

We test the performance of the Polarizable Embedding Variational Quantum Eigensolver Self-Consistent-Field (PE-VQE-SCF) model for computing electric field gradients with comparisons to conventional complete active space…

Different numerical approaches for the stray-field calculation in the context of micromagnetic simulations are investigated. We compare finite difference based fast Fourier transform methods, tensor grid methods and the finite-element…

Computational Physics · Physics 2014-10-27 Claas Abert , Lukas Exl , Gunnar Selke , André Drews , Thomas Schrefl

The simulation of electronic properties is a pivotal issue in modern electronic structure theory, driving significant efforts over the past decades to develop protocols for computing energy derivatives. In this work, we address this problem…

This paper presents enhancement strategies for the Hermitian and skew-Hermitian splitting method based on gradient iterations. The spectral properties are exploited for the parameter estimation, often resulting in a better convergence. In…

Numerical Analysis · Mathematics 2020-07-08 Qinmeng Zou , Frederic Magoules

We are interested in the online prediction of the electricity load, within the Bayesian framework of dynamic models. We offer a review of sequential Monte Carlo methods, and provide the calculations needed for the derivation of so-called…

Applications · Statistics 2013-04-16 Tristan Launay , Anne Philippe , Sophie Lamarche

A general method for calculating \NLO cross sections in perturbative QCD is presented. The algorithm is worked out for calculating $N$-jet cross sections in hadron-hadron collisions. The generalization of the scheme to performing…

High Energy Physics - Phenomenology · Physics 2009-10-30 Zoltán Nagy , Zoltán Trócsányi