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The theoretical development of quasi-Monte Carlo (QMC) methods for uncertainty quantification of partial differential equations (PDEs) is typically centered around simplified model problems such as elliptic PDEs subject to homogeneous zero…

Numerical Analysis · Mathematics 2025-03-26 Laura Bazahica , Vesa Kaarnioja , Lassi Roininen

We consider the scattering matrix approach to quantum electron transport in meso- and nano-conductors. This approach is an alternative to the more conventional kinetic equation and Green's function approaches, and often is more efficient…

Mesoscale and Nanoscale Physics · Physics 2015-04-09 G. B. Lesovik , I. A. Sadovskyy

The quasi parton distribution is a spatial correlation of quarks or gluons along the $z$ direction in a moving nucleon which enables direct lattice calculations of parton distribution functions. It can be defined with a nonperturbative…

High Energy Physics - Phenomenology · Physics 2018-03-28 Iain W. Stewart , Yong Zhao

A quasimodal expansion method (QMEM) is developed to model and understand the scattering properties of arbitrary shaped two-dimensional (2-D) open structures. In contrast with the bounded case which have only discrete spectrum (real in the…

The local-field (LF) problem of a finite-size dipole emit- ter radiating inside a lossy inhomogeneous structure is a long-standing and challenging quantum optical problem, and it now is becoming more important due to rapid advances in…

Mesoscale and Nanoscale Physics · Physics 2015-04-14 Rong-Chun Ge , Jeff F. Young , S. Hughes

The inverse wave scattering problem seeks to estimate a heterogeneous, inaccessible medium, modeled by unknown variable coefficients in wave equations, from transient recordings of waves generated by probing signals. It is a widely studied…

Numerical Analysis · Mathematics 2024-03-07 Liliana Borcea , Yiyang Liu , Jörn Zimmerling

The objective of this contribution is to compare two methods proposed recently in order to build efficient reduced-order models for geometrically nonlinear structures. The first method relies on the normal form theory that allows one to…

Numerical Analysis · Mathematics 2022-02-22 Alessandra Vizzaccaro , Loïc Salles , Cyril Touzé

Quasi-stationary distributions (QSDs)arise from stochastic processes that exhibit transient equilibrium behaviour on the way to absorption QSDs are often mathematically intractable and even drawing samples from them is not straightforward.…

Computation · Statistics 2017-01-18 Adam Griffin , Paul A. Jenkins , Gareth O. Roberts , Simon E. F. Spencer

The quasidiffusion (QD) method, also known as the Variable Eddington Factor (VEF) method in the astrophysical community, is an established iterative method for accelerating source iterations in SN calculations. A great advantage of the QD…

Numerical Analysis · Mathematics 2024-10-14 Dean Wang

We consider unconstrained stochastic optimization problems with no available gradient information. Such problems arise in settings from derivative-free simulation optimization to reinforcement learning. We propose an adaptive sampling…

Optimization and Control · Mathematics 2021-09-28 Raghu Bollapragada , Stefan M. Wild

This paper presents a simple model that mimics quantum mechanics (QM) results in terms of probability fields of free particles subject to self-interference, without using Schroedinger equation or complex wavefunctions. Unlike the standard…

Quantum Physics · Physics 2015-06-03 Antonio Sciarretta

We present a diagrammatic Monte Carlo method for quantum impurity problems with general interactions and general hybridization functions. Our method uses a recursive determinant scheme to sample diagrams for the scattering amplitude. Unlike…

Strongly Correlated Electrons · Physics 2020-08-13 Jia Li , Markus Wallerberger , Emanuel Gull

This paper presents two methods for approximating the performance of coded multicarrier systems operating over frequency-selective, quasi-static fading channels with non-ideal interleaving. The first method is based on approximating the…

Information Theory · Computer Science 2007-07-13 C. Snow , L. Lampe , R. Schober

We construct a class of real-valued nonnegative binary functions on a set of jointly distributed random variables, which satisfy the triangle inequality and vanish at identical arguments (pseudo-quasi-metrics). These functions are useful in…

Probability · Mathematics 2016-02-12 Ehtibar N. Dzhafarov , Janne V. Kujala

Many problems in geometric optics or convex geometry can be recast as optimal transport problems: this includes the far-field reflector problem, Alexandrov's curvature prescription problem, etc. A popular way to solve these problems…

Numerical Analysis · Mathematics 2017-03-08 Jun Kitagawa , Quentin Mérigot , Boris Thibert

We introduce a reduced order model (ROM) methodology for inverse electromagnetic wave scattering in layered lossy media, using data gathered by an antenna which generates a probing wave and measures the time resolved reflected wave. We…

Dynamical Systems · Mathematics 2021-08-04 Liliana Borcea , Vladimir Druskin , Jörn Zimmerling

The aim of this paper is to develop and analyze numerical schemes for approximately solving the backward problem of subdiffusion equation involving a fractional derivative in time with order $\alpha\in(0,1)$. After using quasi-boundary…

Numerical Analysis · Mathematics 2020-10-28 Zhengqi Zhang , Zhi Zhou

We solve the radiative transfer equation (RTE) in anisotropically scattering media as an infinite series. Each series term represents a distinct number of scattering events, with analytical solutions derived for zero and single scattering.…

High Energy Physics - Phenomenology · Physics 2024-07-25 Vladimir Allakhverdian , Dmitry V. Naumov

A randomized Gram-Schmidt algorithm is developed for orthonormalization of high-dimensional vectors or QR factorization. The proposed process can be less computationally expensive than the classical Gram-Schmidt process while being at least…

Numerical Analysis · Mathematics 2022-01-20 Oleg Balabanov , Laura Grigori

The radiative transfer equation (RTE) is a cornerstone for describing the propagation of electromagnetic radiation in a medium, with applications spanning atmospheric science, astrophysics, remote sensing, and biomedical optics. Despite its…

Optics · Physics 2024-01-19 Vladimir Allaxwerdian , Dmitry V. Naumov