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Wave effects in lensing form a rich phenomenon at the intersection of classical caustic singularities and quantum interference, yet are notoriously difficult to model. A large number of recently observed pulsars and fast radio bursts in…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-01 Job Feldbrugge

A class of algorithms for the solution of discrete material optimization problems in electromagnetic applications is discussed. The idea behind the algorithm is similar to that of the sequential programming. However, in each major iteration…

Optimization and Control · Mathematics 2017-07-14 Johannes Semmler , Lukas Pflug , Michael Stingl

Geometrical optics (GO) is often used to model wave propagation in weakly inhomogeneous media and quantum-particle motion in the semiclassical limit. However, GO predicts spurious singularities of the wavefield near reflection points and,…

Optics · Physics 2020-09-10 N. A. Lopez , I. Y. Dodin

The Expectation--Maximization (EM) algorithm is a simple meta-algorithm that has been used for many years as a methodology for statistical inference when there are missing measurements in the observed data or when the data is composed of…

Machine Learning · Statistics 2022-11-15 Hideitsu Hino , Shotaro Akaho , Noboru Murata

A semi-analytical computational algorithm to model the wavefield generated by paraxial diffraction of a class of Laguerre-Gauss beams by sharp-edge elliptic apertures is here developed. Thanks to such a powerful computational tool, some…

Optics · Physics 2024-02-05 Riccardo Borghi

Computational methods for electromagnetic and light scattering can be used for the calculation of optical forces and torques. Since typical particles that are optically trapped or manipulated are on the order of the wavelength in size,…

We extend the T-matrix approach to light scattering by spherical particles to some simple cases in which the scatterers are optically anisotropic. Specifically we consider cases in which the spherical particles include radially and…

Optics · Physics 2009-11-07 A. D. Kiselev , V. Yu Reshetnyak , T. J. Sluckin

The optical matrix formalism is applied to find parameters such as focal distance, back and front focal points, principal planes, and the equation relating object and image distances for a thick spherical lens immerse in air. Then, the…

Optics · Physics 2021-08-20 Fulvio Andres Callegari

When gravitational waves propagate near massive objects, their paths curve resulting in gravitational lensing, which is expected to be a promising new instrument in astrophysics. If the time delay between different paths is comparable with…

General Relativity and Quantum Cosmology · Physics 2022-07-14 Oleg Bulashenko , Helena Ubach

We prove that the electromagnetic material parameters are uniquely determined by boundary measurements for the time-harmonic Maxwell equations in certain anisotropic settings. We give a uniqueness result in the inverse problem for Maxwell…

Analysis of PDEs · Mathematics 2019-12-19 Carlos E. Kenig , Mikko Salo , Gunther Uhlmann

Many naturally-occuring models in the sciences are well-approximated by simplified models, using multiscale techniques. In such settings it is natural to ask about the relationship between inverse problems defined by the original problem…

Numerical Analysis · Mathematics 2019-02-28 Kit Newton , Qin Li , Andrew Stuart

A hybrid physical and geometrical optics method is proposed to model the subsurface imaging using mmWave FMCW radar. Modeling of the wave propagation for subsurface imaging can improve the interpretation of acquired data and imaging…

Signal Processing · Electrical Eng. & Systems 2026-04-14 Kaito Ichijo , Hang Song , Xin Du , Bo Wei , Junichi Takada

We develop a path integrals approach for analyzing stationary light propagation appropriate for photonic crystals. The hermitian form of the stationary Maxwell equations is transformed into a quantum mechanical problem of a spin 1 particle…

Optics · Physics 2009-04-01 Yair Dimant , Shimon Levit

In this paper we construct a parametrix for the fractional Helmholtz equation $((-\Delta)^s - \tau^{2s} r(x)^{2s} + q(x))u=0$ making use of geometrical optics solutions. We show that the associated eikonal equation is the same as in the…

Analysis of PDEs · Mathematics 2024-12-20 Giovanni Covi , Maarten de Hoop , Mikko Salo

Although Bayesian methods are robust and principled, their application in practice could be limited since they typically rely on computationally intensive Markov Chain Monte Carlo algorithms for their implementation. One possible solution…

Computation · Statistics 2015-10-06 Tian Chen , Jeffrey Streets , Babak Shahbaba

Multipole expansion of an incident radiation field - that is, representation of the fields as sums of vector spherical wavefunctions - is essential for theoretical light scattering methods such as the T-matrix method and generalised…

Optics · Physics 2007-05-23 T. A. Nieminen , H. Rubinsztein-Dunlop , N. R. Heckenberg

This paper presents a mathematical framework for analyzing machine learning models through the geometry of their induced partitions. By representing partitions as Riemannian simplicial complexes, we capture not only adjacency relationships…

Machine Learning · Computer Science 2025-08-05 Pawel Gajer , Jacques Ravel

Maxwell's equations are cast in the form of the Schr\"{o}dinger equation. The Lanczos propagation method is used in combination with the fast Fourier pseudospectral method to solve the initial value problem. As a result, a time-domain,…

Computational Physics · Physics 2007-05-23 Andrei G. Borisov , Sergei V. Shabanov

The propagation of a wave in a medium is generally affected when the medium is moving with respect to the observer. Because plasma equilibria often involve plasma flows, for instance in astrophysics or in magnetic confinement nuclear fusion…

Plasma Physics · Physics 2024-07-22 Aymeric Braud , Julien Langlois , Renaud Gueroult

We study the systematic numerical approximation of Maxwell's equations in dispersive media. Two discretization strategies are considered, one based on a traditional leapfrog time integration method and the other based on convolution…

Numerical Analysis · Mathematics 2020-04-02 Jürgen Dölz , Herbert Egger , Vsevolod Shashkov