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Free-space propagation can be described as a shearing of the Wigner distribution function in the spatial coordinate; this shearing is linear in paraxial approximation but assumes a more complex shape for wide-angle propagation. Integration…

Optics · Physics 2009-11-10 J. B. Almeida , V. Lakshminarayanan

In the two space dimensions of screens in optical sy stems, rotations, gyrations, and fractional Fourier transformations form the Fourier subgroup of the symplectic group of linear canonical transformations: U(2) F $\subset$ Sp(4,R). Here…

Mathematical Physics · Physics 2022-04-11 Alejandro R. Urzúa , Kurt Bernardo Wolf

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…

Numerical Analysis · Mathematics 2024-03-26 Clemens Kirisits , Noemi Naujoks , Otmar Scherzer

We consider the probe of astrophysical signals through radio interferometers with small field of view and baselines with non-negligible and constant component in the pointing direction. In this context, the visibilities measured essentially…

Instrumentation and Methods for Astrophysics · Physics 2009-11-16 Y. Wiaux , G. Puy , Y. Boursier , P. Vandergheynst

Elongation of the point spread function due to atmospheric dispersion becomes a severe problem for high resolution imaging instruments, if an atmospheric dispersion corrector is not present. In this work we report on a novel technique to…

Instrumentation and Methods for Astrophysics · Physics 2022-04-06 J. A. van den Born , W. Jellema , E. Dijkstra

In most theories of diffraction by a diaphragm, the amplitude of the diffracted wave, and hence the position wave function of the associated particle, is calculated directly without prior calculation of the quantum state. Few models express…

Quantum Physics · Physics 2024-10-29 Bernard Fabbro

High quality, repeatable point-spread functions are important for science cases like direct exoplanet imaging, high-precision astrometry, and high-resolution spectroscopy of exoplanets. For such demanding applications, the initial on-sky…

Instrumentation and Methods for Astrophysics · Physics 2021-07-19 Steven P. Bos , Michael Bottom , Sam Ragland , Jacques-Robert Delorme , Sylvain Cetre , Laurent Pueyo

The final goal of the present work is to extend the Fourier transform on the Heisenberg group $\H^d,$ to tempered distributions. As in the Euclidean setting, the strategy is to first show that the Fourier transform is an isomorphism on the…

Functional Analysis · Mathematics 2017-05-08 Hajer Bahouri , Jean-Yves Chemin , Raphael Danchin

This Point spread function (PSF) plays a crucial role in many computational imaging applications, such as shape from focus/defocus, depth estimation, and fluorescence microscopy. However, the mathematical model of the defocus process is…

Computer Vision and Pattern Recognition · Computer Science 2022-09-20 Renzhi He , Yan Zhuang , Boya Fu , Fei Liu

The diffraction spectra of the Hat and Spectre monotile tilings, which are known to be pure point, are derived and computed explicitly. This is done via model set representatives of self-similar members in the topological conjugacy classes…

Metric Geometry · Mathematics 2025-10-03 Michael Baake , Franz Gähler , Jan Mazáč , Andrew Mitchell

The change of the effective dimension of spacetime with the probed scale is a universal phenomenon shared by independent models of quantum gravity. Using tools of probability theory and multifractal geometry, we show how dimensional flow is…

High Energy Physics - Theory · Physics 2012-08-16 Gianluca Calcagni

Recent experimental work has demonstrated the potential to combine the merits of diffractive and on-chip photonic information processing devices in a single chip by making use of planar (or slab) waveguides. Researchers have adapted key…

Optics · Physics 2023-05-26 Benjamin Wetherfield , Timothy D. Wilkinson

Ground based optical telescopes are seriously affected by atmospheric turbulence induced aberrations. Understanding properties of these aberrations is important both for instruments design and image restoration methods development. Because…

Instrumentation and Methods for Astrophysics · Physics 2020-04-08 Peng Jia , Xuebo Wu , Yi Huang , Bojun Cai , Dongmei Cai

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…

Instrumentation and Methods for Astrophysics · Physics 2024-07-17 Peter Wortmann , James Kent , Bojan Nikolic

We present new advances in the spectral extraction of point-like sources adapted to the Infrared Spectrograph onboard the Spitzer Space Telescope. For the first time, we created a super-sampled point spread function of the low-resolution…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 V. Lebouteiller , J. Bernard-Salas , G. C. Sloan , D. J. Barry

The photon density operator function is used to calculate light beam propagation through turbulent atmosphere. A kinetic equation for the photon distribution function is derived and solved using the method of characteristics. Optical wave…

Quantum Physics · Physics 2009-11-13 G. P. Berman , A. A. Chumak

Diffusion models provide a principled framework for generative modeling via stochastic differential equations and time-reversed dynamics. Extending spectral diffusion approaches to spherical data, however, raises nontrivial geometric and…

Probability · Mathematics 2026-01-29 Pierpaolo Brutti , Claudio Durastanti , Francesco Mari

In this work we introduce a new measure for the dispersion of the spectral scale of a Hermitian (self-adjoint) operator acting on a separable infinite dimensional Hilbert space that we call spectral spread. Then, we obtain some…

Functional Analysis · Mathematics 2022-10-18 Pedro Massey , Demetrio Stojanoff , Sebastian Zarate

High precision cosmology with weak gravitational lensing requires a precise measure of the Point Spread Function across the imaging data where the accuracy to which high spatial frequency variation can be modelled is limited by the stellar…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Catherine Heymans , Barnaby Rowe , Henk Hoekstra , Lance Miller , Thomas Erben , Thomas Kitching , Ludovic Van Waerbeke

Fourier transforms are ubiquitous mathematical tools in basic and applied sciences. We here report classical and quantum optical realizations of the discrete fractional Fourier transform, a generalization of the Fourier transform. In the…

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