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Hyperbolic partial differential equations (PDEs) cover a wide range of interesting phenomena, from human and hearth-sciences up to astrophysics: this unavoidably requires the treatment of many space and time scales in order to describe at…

Numerical Analysis · Mathematics 2022-09-07 Elena Gaburro , Simone Chiocchetti

Understanding a behavior of galaxy biasing is crucial for future galaxy redshift surveys. One aim is to measure the baryon acoustic oscillations (BAOs) within the precision of a few percent level. Using 30 large cosmological N-body…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-12 Masanori Sato , Takahiko Matsubara

Some recently proposed approximations to follow the non--linear evolution of collisionless matter perturbations in the universe are reviewed. The first one, called frozen--flow approximation, is an Eulerian method within Newtonian theory,…

Astrophysics · Physics 2007-05-23 S. Matarrese , P. Catelan , F. Lucchin , L. Moscardini , O. Pantano , D. Saez

The cosmological model consisting of a nonlinear magnetic field obeying the Lagrangian L= \gamma F^{\alpha}, F being the electromagnetic invariant, coupled to a Robertson-Walker geometry is tested with observational data of Type Ia…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-12 Ariadna Montiel , Nora Bretón , Vincenzo Salzano

We propose and experimentally demonstrate an efficient image decomposition in the Laguerre-Gaussian (LG) domain. By developing an advanced computing method, the sampling points are much fewer than those in the existing methods, which can…

Image and Video Processing · Electrical Eng. & Systems 2020-05-19 Jiantao Ma , Dan Wei , Haocheng Yang , Yong Zhang , Min Xiao

The large-scale structure of the Universe is thought to evolve by a process of gravitational amplification from low-amplitude Gaussian noise generated in the early Universe. The later, non-linear stages of gravitation-induced clustering…

Astrophysics · Physics 2009-11-07 Peter Watts , Peter Coles , Adrian Melott

We consider a new variant of cosmological perturbation theory that has been designed specifically to include non-linear density contrasts on scales 100 Mpc, while still allowing for linear fluctuations on larger scales. This theory is used…

General Relativity and Quantum Cosmology · Physics 2019-04-08 Christopher S. Gallagher , Timothy Clifton

In this paper we describe the construction of an efficient probabilistic parameterization that could be used in a coarse-resolution numerical model in which the variation of moisture is not properly resolved. An Eulerian model using a…

Atmospheric and Oceanic Physics · Physics 2018-10-30 Yue-Kin Tsang , Geoffrey K. Vallis

Lagrangian averaging plays an important role in the analysis of wave--mean-flow interactions and other multiscale fluid phenomena. The numerical computation of Lagrangian means, e.g. from simulation data, is however challenging. Typical…

Fluid Dynamics · Physics 2023-04-26 Hossein A. Kafiabad , Jacques Vanneste

Observations of galaxy clustering are made in redshift space, which results in distortions to the underlying isotropic distribution of galaxies. These redshift-space distortions (RSD) not only degrade important features of the matter…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-29 Yuchan Wang , Baojiu Li , Marius Cautun

There is a growing attention given to utilizing Lagrangian and Hamiltonian mechanics with network training in order to incorporate physics into the network. Most commonly, conservative systems are modeled, in which there are no frictional…

Machine Learning · Computer Science 2024-05-28 Veera Sundararaghavan , Megna N. Shah , Jeff P. Simmons

Clustering is a cornerstone of modern data analysis. Detecting clusters in exploratory data analyses (EDA) requires algorithms that make few assumptions about the data. Density-based clustering algorithms are particularly well-suited for…

Machine Learning · Computer Science 2026-02-03 Daniël Bot , Leland McInnes , Jan Aerts

Data-driven, model-free analytics are natural choices for discovery and forecasting of complex, nonlinear systems. Methods that operate in the system state-space require either an explicit multidimensional state-space, or, one approximated…

Machine Learning · Statistics 2021-03-15 Joseph Park , Gerald M Pao , Erik Stabenau , George Sugihara , Thomas Lorimer

We present an algorithm for quickly generating multiple realizations of N-body simulations to be used, for example, for cosmological parameter estimation from surveys of large-scale structure. Our algorithm uses a new method to resample the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Michael D. Schneider , Shaun Cole , Carlos S. Frenk , Istvan Szapudi

Reconstructing the initial density field of the Universe from the late-time matter distribution is a nontrivial task with implications for understanding structure formation in cosmology, offering insights into early Universe conditions.…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-26 Koichiro Nakashima , Kiyotomo Ichiki , Atsushi J. Nishizawa , Kenji Hasegawa

The main purpose of this work is the mathematical modelling of large populations of cells under different deterministic interactions among themselves, in balance with naturally random diffusion. We focus on cell-cell adhesion mechanisms for…

Analysis of PDEs · Mathematics 2025-03-19 Carlo Giambiagi Ferrari , Francisco Guillen-Gonzalez , Mayte Perez-Llanos , Antonio Suarez

The space Loc(m,S) of rank m flat bundles on a closed surface S is K_2-symplectic. A threefold M bounding S gives rise a K_2-Lagrangian in Loc(m,S) given by the flat bundles on S extending to M. We generalize this, replacing the zero…

Algebraic Geometry · Mathematics 2026-01-13 Alexander B. Goncharov , Maxim Kontsevich

Reconstructing cosmological initial conditions (ICs) from late-time observations is a difficult task, which relies on the use of computationally expensive simulators alongside sophisticated statistical methods to navigate multi-million…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-22 Oleg Savchenko , Florian List , Guillermo Franco Abellán , Noemi Anau Montel , Christoph Weniger

The long wavelength modes lost to bright foregrounds in the interferometric 21-cm surveys can partially be recovered using a forward modeling approach that exploits the non-linear coupling between small and large scales induced by…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-27 Chirag Modi , Martin White , Emanuele Castorina , Anže Slosar
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