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The Hubbard model represents the fundamental model for interacting quantum systems and electronic correlations. Using the two-dimensional half-filled Hubbard model at weak coupling as a testing ground, we perform a comparative study of a…

This paper discusses the Cosmic Background (CB) dipoles observations in the framework of the Planck mission. Dipoles observations can be used in three ways: (i) It gives a measurement of the peculiar velocity of our Galaxy which is an…

Astrophysics · Physics 2009-11-07 M. Piat , G. Lagache , J. P. Bernard , M. Giard , J. L. Puget

Intensity mapping of 21cm emission from neutral hydrogen promises to be a powerful probe of large-scale structure in the post-reionisation epoch. However, HI intensity mapping (IM) experiments will suffer the loss of long-wavelength…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-30 Kavilan Moodley , Warren Naidoo , Heather Prince , Aurelie Penin

The fast multipole method (FMM) performs fast approximate kernel summation to a specified tolerance $\epsilon$ by using a hierarchical division of the domain, which groups source and receiver points into regions that satisfy local…

Numerical Analysis · Computer Science 2012-04-17 Yuancheng Luo , Ramani Duraiswami

Instrument models (IMs) enable the reduction of systematic error in transit spectroscopy light curve data, but, since the model formulation can influence the estimation of science model parameters, characterization of the instrument model…

Instrumentation and Methods for Astrophysics · Physics 2022-01-05 Noah Huber-Feely , Mark R. Swain , Gael Roudier , Raissa Estrela

Fractal Interpolation has been proposed in the literature as an efficient way to construct closure models for the numerical solution of coarse-grained Navier-Stokes equations. It is based on synthetically generating a scale-invariant…

Fluid Dynamics · Physics 2016-08-16 Sukanta Basu , Efi Foufoula-Georgiou , Fernando Porté-Agel

The use of integral equation methods for the efficient numerical solution of PDE boundary value problems requires two main tools: quadrature rules for the evaluation of layer potential integral operators with singular kernels, and fast…

Numerical Analysis · Mathematics 2017-06-28 Manas Rachh , Andreas Klöckner , Michael O'Neil

Microwave remote sensing offers a powerful tool for monitoring the growth of short, dense vegetation like soybean. As the plants mature, changes in their biomass and 3-D structure impact the electromagnetic (EM) backscatter signal. This…

We present quantitative means for assessing the numerical accuracy of static magnetic field calculations in finite-element models. Our calculations use the three-dimensional Opera simulation software suite of Dassault Syst`emes. Our need to…

Accelerator Physics · Physics 2021-06-03 J. A. Crittenden

In many practical applications of numerical methods a substantial increase in efficiency can be obtained by using local grid refinement, since the solution is generally smooth in large parts of the domain and large gradients occur only…

Numerical Analysis · Mathematics 2016-06-21 E. H. van Brummelen , C. H. Venner

In this paper, we will introduce a new heterogeneous fast multipole method (H-FMM) for 2-D Helmholtz equation in layered media. To illustrate the main algorithm ideas, we focus on the case of two and three layers in this work. The key…

Numerical Analysis · Mathematics 2018-07-04 Min Hyung Cho , Jingfang Huang , Dangxing Chen , Wei Cai

Given a multimodal interval map $f:I \to I$ and a H\"older potential $\phi:I \to \mathbb{R}$, we study the dimension spectrum for equilibrium states of $\phi$. The main tool here is inducing schemes, used to overcome the presence of…

Dynamical Systems · Mathematics 2009-11-16 Mike Todd

In this paper, the channel of an indoor holographic multiple-input multiple-output (MIMO) system is measured. It is demonstrated through experiments for the first time that the spatial oversampling of holographic MIMO systems is able to…

Information Theory · Computer Science 2023-01-16 Tengjiao Wang , Yongxi Liu , Ming Zhang , Wei E. I. Sha , Cen Ling , Chao Li , Shaobo Wang

21 cm intensity mapping has arisen as a powerful probe of the high-redshift universe, but its potential is limited by extremely bright foregrounds and high source confusion. In this Letter, we propose a new analysis which can help solve…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-11 Patrick C. Breysse , Christopher J. Anderson , Philippe Berger

We present a comprehensive analysis of the 21 cm intensity mapping (IM) data from the Tianlai Cylinder Pathfinder Array (TCPA), focusing on multi-scale foreground mitigation and three-dimensional power spectrum estimation. Utilizing 20 days…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-01 Yikai Deng , Shifan Zuo , Jixia Li , Yougang Wang , Xuelei Chen

We investigate the effect of observational constraints such as signal-to-noise, resolution and column density level on the HI morphological asymmetry ($\mathrm{A}_\mathrm{mod}$) and the effect of noise on the HI global profile…

Astrophysics of Galaxies · Physics 2022-06-08 P. V. Bilimogga , K. A. Oman , M. A. W. Verheijen , J. M. van der Hulst

Accurate mock catalogues are essential for assessing systematics in the cosmological analysis of large galaxy surveys. Anisotropic two-point clustering measurements from the same simulation show some scatter for different lines of sight…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-07 Alex Smith , Arnaud de Mattia , Etienne Burtin , Chia-Hsun Chuang , Cheng Zhao

In real-world sampling of k-space data, one generally makes a stochastic error not only in the value of the sample but in the effective position of the drawn sample. We refer to the latter as imprecise sampling and apply this concept to the…

Other Condensed Matter · Physics 2007-05-23 R. A. Hanel , S. De Backer , J. Sijbers , P. Scheunders

Line intensity mapping experiments seek to trace large scale structure by measuring the spatial fluctuations in the combined emission, in some convenient spectral line, from individually unresolved galaxies. An important systematic concern…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-20 Adam Lidz , Jessie Taylor

Filaments stand as pivotal structures within the cosmic web. However, direct detection of the cold gas content of the filaments remains challenging due to its inherent low brightness temperature. With the TNG hydrodynamical simulations, we…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-10 Diyang Liu , Yichao Li , Denis Tramonte , Furen Deng , Jiaxin Wang , Yougang Wang , Xin Zhang , Xuelei Chen