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Observations of microwave background fluctuations can yield information not only about the geometry of the universe, but potentially about the topology of the universe. If the universe is negatively curved, then the characteristic scale for…

Astrophysics · Physics 2009-10-30 Neil J. Cornish , David N. Spergel , Glenn D. Starkman

This work is concerned with a representation of shapes that disentangles fine, local and possibly repeating geometry, from global, coarse structures. Achieving such disentanglement leads to two unrelated advantages: i) a significant…

Computer Vision and Pattern Recognition · Computer Science 2022-04-06 Luca Morreale , Noam Aigerman , Paul Guerrero , Vladimir G. Kim , Niloy J. Mitra

Over the last decades, cosmological simulations of galaxy formation have been instrumental for advancing our understanding of structure and galaxy formation in the Universe. These simulations follow the non-linear evolution of galaxies…

Astrophysics of Galaxies · Physics 2019-12-20 Mark Vogelsberger , Federico Marinacci , Paul Torrey , Ewald Puchwein

Chi-square histogram distance is one of the distance measures that can be used to find dissimilarity between two histograms. Motivated by the fact that texture discrimination by human vision system is based on second-order statistics, we…

Computer Vision and Pattern Recognition · Computer Science 2012-12-04 V. Asha , N. U. Bhajantri , P. Nagabhushan

We present numerical relativity simulations of cosmological scenarios in which the universe is smoothed and flattened by undergoing a phase of slow contraction and test their sensitivity to a wide range of initial conditions. Our numerical…

General Relativity and Quantum Cosmology · Physics 2020-08-14 Anna Ijjas , William G. Cook , Frans Pretorius , Paul J. Steinhardt , Elliot Y. Davies

We investigate to what extent the cosmic crystallographic methods aimed to detect the topology of the universe using catalogues of cosmic objects would be damaged by various observational uncertainties. We find that the topological…

Astrophysics · Physics 2011-05-23 Roland Lehoucq , Jean-Philippe Uzan , Jean-Pierre Luminet

At early times dark matter has a thermal velocity dispersion of unknown amplitude which, for warm dark matter models, can influence the formation of nonlinear structure on observable scales. We propose a new scheme to simulate cosmologies…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-10 Jens Stücker , Oliver Hahn , Raul E. Angulo , Simon D. M. White

``One could imagine that as a result of enormously extended astronomical experience, the entire universe consists of countless identical copies of our Milky Way, that the infinite space can be partitioned into cubes each containing an…

Astrophysics · Physics 2007-05-23 Jean-Pierre Luminet , Boudewijn F. Roukema

For problems in astrophysics, planetary science and beyond, numerical simulations are often limited to simulating fewer particles than in the real system. To model collisions, the simulated particles (aka superparticles) need to be inflated…

Earth and Planetary Astrophysics · Physics 2020-06-03 David Nesvorny , Andrew N. Youdin , Raphael Marschall , Derek C. Richardson

Many extensions of the Standard Model predict large numbers of additional unstable particles whose decays in the early universe are tightly constrained by observational data. For example, the decays of such particles can alter the ratios of…

High Energy Physics - Phenomenology · Physics 2019-02-20 Keith R. Dienes , Jason Kumar , Patrick Stengel , Brooks Thomas

Topological defects are ubiquitous in condensed-matter physics but only hypothetical in the early universe. In spite of this, even an indirect evidence for one of these cosmic objects would revolutionize our vision of the cosmos. We give…

Astrophysics · Physics 2007-05-23 Alejandro Gangui

The subject of the paper is the geometry and topology of cosmological spacetimes and vector bundles thereon, which are used to model physical fields propagating in the universe. Global hyperbolicity and factorization properties of the…

Mathematical Physics · Physics 2021-03-31 Zhirayr Avetisyan

The global topology of the Universe could, in principle, affect quantum systems through boundary condition constraints. We investigate this connection by analyzing how compact, flat, cosmologically inspired topologies, specifically the…

Quantum Physics · Physics 2025-05-14 Evangelos Achilleas Paraskevas , Leandros Perivolaropoulos

(To appear in Nuclear Physics B Supplements Proceedings section) This talk will explore the evolution of topological defects in an open universe. The rapid expansion of the universe in an open model slows defects and suppresses the…

Astrophysics · Physics 2009-10-22 David N. Spergel , Ue-Li Pen

Multi-connected Universe models with space idenfication scales smaller than the size of the observable universe produce topological images in the catalogs of cosmic sources. In this review, we present the recent developments for the search…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Jean-Philippe Uzan , Roland Lehoucq , Jean-Pierre Luminet

We study the formation of topological textures in a nonequilibrium phase transition of an overdamped classical O(3) model in 2+1 dimensions. The phase transition is triggered through an external, time-dependent effective mass, parameterized…

High Energy Physics - Phenomenology · Physics 2009-10-31 G. J. Stephens

The science of fractography revolves around the correlation between topographic characteristics of the fracture surface and the mechanisms and external conditions leading to their creation. While being a topic of investigation for…

Image and Video Processing · Electrical Eng. & Systems 2020-05-11 Stylianos Tsopanidis , Raúl Herrero Moreno , Shmuel Osovski

The scaling properties of one-dimensional deconstructed surfaces are studied by numerical simulations of a disaggregation model. The model presented here for the disaggregation process takes into account the possibility of having quenched…

Statistical Mechanics · Physics 2007-05-23 Juan R. Sanchez

Mechanically quenching a thin film of smectic-C liquid crystal results in the formation of a dense array of thousands of topological defects in the director field. The subsequent rapid coarsening of the film texture by the mutual…

Soft Condensed Matter · Physics 2023-04-19 Ravin A. Chowdhury , Adam A. S. Green , Cheol S. Park , Joseph E. Maclennan , Noel A. Clark

We provide numerical evidence for the existence of a cascade of filament instabilities in the surface quasigeostrophic system for atmospheric and oceanic motions near a horizontal boundary. The cascade involves geometrically shrinking…

Fluid Dynamics · Physics 2015-06-17 R. K. Scott , D. G. Dritschel