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Cylindrical re-entrant cavities are unique three-dimensional structures that resonate with their electric and magnetic fields in separate parts of the cavity. To further understand these devices, we undertake rigorous analysis of the…

Instrumentation and Detectors · Physics 2015-06-16 J-M. Le Floch , Y. Fan , M. Aubourg , D. Cros , N. C. Carvalho , Q. Shan , J. Bourhill , E. N. Ivanov , G. Humbert , V. Madrangeas , M. E. Tobar

Gravitational lensing offers unique opportunities to learn about the astrophysical origin of distant sources, the abundance of intervening objects acting as lenses, and gravity and cosmology in general. However, all this information can…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-20 Anson Chen , Paolo Cremonese , Jose María Ezquiaga , David Keitel

Learning-based methods for blind single image super resolution (SISR) conduct the restoration by a learned mapping between high-resolution (HR) images and their low-resolution (LR) counterparts degraded with arbitrary blur kernels. However,…

Computer Vision and Pattern Recognition · Computer Science 2023-05-24 Yuxiao Li , Zhiming Wang , Yuan Shen

Whereas considerable effort has been afforded in understanding the properties of galaxies, a full physical picture, connecting their baryonic and dark-matter content, super-massive black holes, and (metric) theories of gravity, is still…

We present a novel probabilistic finite element method (FEM) for the solution and uncertainty quantification of elliptic partial differential equations based on random meshes, which we call random mesh FEM (RM-FEM). Our methodology allows…

Numerical Analysis · Mathematics 2021-06-17 Assyr Abdulle , Giacomo Garegnani

Using diffusion models to solve inverse problems is a growing field of research. Current methods assume the degradation to be known and provide impressive results in terms of restoration quality and diversity. In this work, we leverage the…

Computer Vision and Pattern Recognition · Computer Science 2025-06-02 Charles Laroche , Andrés Almansa , Eva Coupete

We study the gravitational lensing scenario where the lens is a spherically symmetric charged black hole (BH) surrounded by quintessence matter. The null geodesic equations in the curved background of the black hole are derived. The…

General Relativity and Quantum Cosmology · Physics 2017-06-21 Mustapha Azreg-Aïnou , Sebastian Bahamonde , Mubasher Jamil

We have reanalysed the 1996/1997 VLA monitoring data of the gravitational lens system JVAS B0218+357 to produce improved total flux density and polarization variability curves at 15, 8.4 and 5 GHz. This has been done using improved…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-21 A. D. Biggs , I. W. A. Browne

We investigate gravitational lensing in the context of the MOG modified theory of gravity. Using a formulation of the theory with no adjustable or fitted parameters, we present the MOG equations of motion for slow, nonrelativistic test…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-04 J. W. Moffat , S. Rahvar , V. T. Toth

This paper introduces a multiscale maximum entropy (MSME) algorithm for image restoration of the Hard X-ray Modulation Telescope (HXMT), which is a collimated scan X-ray satellite mainly devoted to a sensitive all-sky survey and pointed…

Instrumentation and Methods for Astrophysics · Physics 2016-06-03 Ju Guan , Li-Ming Song , Zhuo-Xi Huo

The standard implementation of the Maximum Entropy Method (MEM) follows Bryan and deploys a Singular Value Decomposition (SVD) to limit the dimensionality of the underlying solution space apriori. Here we present arguments based on the…

Computational Physics · Physics 2013-01-08 Alexander Rothkopf

We propose a new technique for weak gravitational lensing in the radio band making use of polarization information. Since the orientation of a galaxy's polarized emission is both unaffected by lensing and is related to the galaxy's…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Michael L. Brown , Richard A. Battye

Studies of weak gravitational lensing by large-scale structures require the measurement of the distortions introduced to the shapes of distant galaxies at the few percent level by anisotropic light deflection along the line of sight. To…

Astrophysics · Physics 2009-11-07 Andrew W. Blain

We propose a new model-independent measurement strategy for the propagation speed of gravitational waves (GWs) based on strongly lensed GWs and their electromagnetic (EM) counterparts. This can be done in two ways: by comparing arrival…

General Relativity and Quantum Cosmology · Physics 2017-04-05 Xi-Long Fan , Kai Liao , Marek Biesiada , Aleksandra Piorkowska-Kurpas , Zong-Hong Zhu

We make remarks on the Maximum Entropy Method (MEM) for studies of the spectral function of hadronic correlators in finite temperature lattice QCD. We discuss the virtues and subtlety of MEM in the cases that one does not have enough number…

High Energy Physics - Lattice · Physics 2007-05-23 Takashi Umeda , Hideo Matsufuru

In this paper we discuss a new method which can be used to obtain arbitrarily accurate analytical expressions for the deflection angle of light propagating in a given metric. Our method works by mapping the integral into a rapidly…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Paolo Amore , Santiago Arceo Diaz

Finding strong gravitational lenses in astronomical images allows us to assess cosmological theories and understand the large-scale structure of the universe. Previous works on lens detection do not quantify uncertainties in lens parameter…

Instrumentation and Methods for Astrophysics · Physics 2022-11-22 Yash Patel , Jeffrey Regier

Wave optics may need to be considered when studying the lensed waveforms of gravitational waves (GWs). However, the computation of the diffraction integral (amplification factor) in wave optics is challenging and time-consuming. It is vital…

General Relativity and Quantum Cosmology · Physics 2021-01-08 Xiao Guo , Youjun Lu

Exploration is essential for solving complex Reinforcement Learning (RL) tasks. Maximum State-Visitation Entropy (MSVE) formulates the exploration problem as a well-defined policy optimization problem whose solution aims at visiting all…

Measuring dark matter substructure within galaxy cluster haloes is a fundamental probe of the Lambda-CDM model of structure formation. Gravitational lensing is a technique for measuring the total mass distribution which is independent of…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-17 Benjamin Cain , Paul L. Schechter , M. W. Bautz