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Weak lensing can be observed through a number of effects on the images of distant galaxies; their shapes are sheared, their sizes and fluxes (magnitudes) are magnified and their positions on the sky are modified by the lensing field. Galaxy…

宇宙学与河外天体物理 · 物理学 2015-08-12 Justin Alsing , Donnacha Kirk , Alan Heavens , Andrew Jaffe

Divergence functions are measures of distance or dissimilarity between probability distributions that serve various purposes in statistics and applications. We propose decompositions of Wasserstein and Cram\'er distances$-$which compare two…

统计方法学 · 统计学 2025-08-08 Johannes Resin , Daniel Wolffram , Johannes Bracher , Timo Dimitriadis

We describe a scalable distributed imaging algorithm framework for next-generation radio telescopes, managing the Fourier transform from apertures to sky (or vice versa) with a focus on minimising memory load, data transfers, and…

天体物理仪器与方法 · 物理学 2024-07-17 Peter Wortmann , James Kent , Bojan Nikolic

Weak gravitational lensing provides a unique method to directly measure the distribution of mass in the universe. Because the distortions induced by lensing in the shape of background galaxies are small, the measurement of weak lensing…

天体物理学 · 物理学 2009-11-06 Alexandre Refregier , David Bacon

We study the wave propagation in nonlinear electrodynamical models. Particular attention is paid to the derivation and the analysis of the Fresnel equation for the wave covectors. For the class of general nonlinear Lagrangian models, we…

广义相对论与量子宇宙学 · 物理学 2009-11-07 Yuri N. Obukhov , Guillermo F. Rubilar

In scattering theory the far field pattern describes the directional dependence of a time-harmonic wave scattered by an obstacle or inhomogeneous medium, when observed sufficiently far away from these objects. Considering plane wave…

偏微分方程分析 · 数学 2012-10-12 Roland Griesmaier , Nuutti Hyvönen , Otto Seiskari

We generalize the notion of the Franhoufer diffraction from a single slit and a circular aperture to the case of partially temporal coherent and quasimonochromatic light. The problem is studied analytically and the effect of coherence…

光学 · 物理学 2019-03-27 E. Koushki , S. A. Alavi

The general method to obtain solutions of the Maxwellian equations from scalar representatives is developed and applied to the diffraction of electromagnetic waves. Kirchhoff's integral is modified to provide explicit expressions for these…

光学 · 物理学 2019-03-27 Ulrich Brosa

Interference of randomly scattered classical waves naturally leads to familiar speckle patterns, where the wave intensity follows an exponential distribution while the wave field itself is described by a circularly symmetric complex normal…

偏微分方程分析 · 数学 2025-10-13 Guillaume Bal , Anjali Nair

We describe a self calibrating optical technique that allows to perform absolute measurements of scattering cross sections for the light scattered at extremely small angles. Very good performances are obtained by using a very simple optical…

光学 · 物理学 2009-11-10 Doriano Brogioli , Alberto Vailati , Marzio Giglio

The majority of stochastic channel models rely on the electromagnetic far-field assumption, which allows to decompose the channel in terms of plane waves. The far-field assumption breaks down in future applications that push towards the…

信息论 · 计算机科学 2022-04-28 Andrea Pizzo , Luca Sanguinetti , Thomas L. Marzetta

Theory predicts that a plane wave scattered by a thin slab of gas yields, in the forward direction and under specific circumstances, a larger irradiance than would be observed in the absence of the gas. This enhanced Rayleigh scattering…

星系天体物理 · 物理学 2012-11-30 Frederic Zagury , Pierre Pellat-Finet

We suggest a scheme to manipulate paraxial diffraction by utilizing the dependency of a four-wave mixing process on the relative angle between the light fields. A microscopic model for four-wave mixing in a Lambda-type level structure is…

光学 · 物理学 2015-06-18 Itay Katzir , Amiram Ron , Ofer Firstenberg

We investigate the electromagnetic propagation in two-dimensional photonic crystals, formed by parallel dielectric cylinders embedded a uniform medium. The frequency band structure is computed using the standard plane-wave expansion method,…

光学 · 物理学 2009-11-10 Liang-Shan Chen , Chao-Hsien Kuo , Zhen Ye

Diffraction tomography is an inverse scattering technique used to reconstruct the spatial distribution of the material properties of a weakly scattering object. The object is exposed to radiation, typically light or ultrasound, and the…

数值分析 · 数学 2024-03-26 Clemens Kirisits , Noemi Naujoks , Otmar Scherzer

Numerical simulation of Fresnel diffraction with fast Fourier transform (FFT) is widely used in optics, especially computer holography. Fresnel diffraction with FFT cannot set different sampling rates between source and destination planes,…

In a frame of quasi-crystal approximation the dispersion equations are obtained for the wave vector of a coherent electromagnetic wave propagating in a media which contains a random set of parallel dielectric cylinders with possible…

光学 · 物理学 2007-05-23 Nadejda L. Cherkas

General properties of linear propagation of discretized light in homogeneous and curved waveguide arrays are comprehensively investigated and compared to those of paraxial diffraction in continuous media. In particular, general laws…

光学 · 物理学 2015-05-14 S. Longhi

Luminous tracers have been used extensively to map the large-scale matter distribution in the Universe. Similarly the dynamics of stars or galaxies can be used to estimate masses of galaxies and clusters of galaxies. However, assumptions…

宇宙学与河外天体物理 · 物理学 2016-11-25 H. Hoekstra

Coherent wave-propagation in the near-field Fresnel-regime is the underlying contrast-mechanism to (propagation-based) X-ray phase contrast imaging (XPCI), an emerging lensless technique that enables 2D- and 3D-imaging of biological soft…

数值分析 · 数学 2018-11-06 Simon Maretzke
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