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Accounting for large-scale structure in our universe will require not only reasonably accurate mathematical models of its cosmogony, topology and cosmology, but also a more deeper understanding of our fundamental physical concepts of space,…

Astrophysics · Physics 2016-08-30 Charles B. Leffert

Matter density is formally infinite at the location of caustic surfaces, where dark matter sheet folds in phase-space. The caustics separate regions with different number of streams and the volume elements change the parity by turning…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-17 Sergei F. Shandarin , Nesar S. Ramachandra

The caustic skeleton model is a mathematically rigorous framework for studying the formation history of the emerging cosmic web from the caustics in the underlying dark matter flow. In a series of two papers, we use constrained N-body…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-06 Benjamin Hertzsch , Job Feldbrugge , Maé Rodriguez , Rien van de Weygaert

I review the nature of three-dimensional collapse in the Zeldovich approximation, how it relates to the underlying nature of the three-dimensional Lagrangian manifold and naturally gives rise to a hierarchical structure formation scenario…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-20 Oliver Hahn

Cold dark matter haloes are populated by high-density structures with sharply-peaked profiles known as caustics which have not yet been resolved by 3-dimensional numerical simulations. Here, we derive semi-analytic expressions for the…

Astrophysics · Physics 2009-11-10 Roya Mohayaee , Sergei Shandarin

Based on the proposed unifying theory of dark matter and quintessence, a novel nonlinear structure formation scenario is suggested. This top-down singular and turbulent scenario results in a bottom-up hierarchical clustering and is…

General Physics · Physics 2007-05-23 Reza Dastvan

The gravitational hydrodynamics of the primordial plasma with neutrino hot dark matter is considered as a challenge to the bottom-up cold dark matter paradigm. Viscosity and turbulence induce a top-down fragmentation scenario before and at…

Cosmology and Nongalactic Astrophysics · Physics 2009-12-08 Theo M. Nieuwenhuizen , Carl H. Gibson , Rudy E. Schild

The gravitational collapse of collisionless matter leads to shell-crossing singularities that challenge the applicability of standard perturbation theory. Here, we present the first fully perturbative approach in three dimensions by using…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-15 Shohei Saga , Stéphane Colombi , Atsushi Taruya , Cornelius Rampf , Abineet Parichha

We study the evolution of density in an expanding Bose-Einstein condensate that initially has a spatially varying phase, concentrating on behaviour when these phase variations are large. In this regime large density fluctuations develop…

Disordered Systems and Neural Networks · Physics 2009-08-07 J. T. Chalker , B. Shapiro

We study the non-linear structure formation in cosmology accounting for the quantum nature of the dark matter (DM) particles in the initial conditions at decoupling, as well as in the relaxation and stability of the DM halos. Differently…

Astrophysics of Galaxies · Physics 2022-03-14 Carlos R. Argüelles , Eduar A. Becerra-Vergara , Andreas Krut , Rafael Yunis , Jorge A. Rueda , Remo Ruffini

The hierarchical cold dark matter (CDM) model for structure formation is a well defined and testable model. Direct detection is the best technique for confirming the model yet predictions for the energy and density distribution of particles…

Astrophysics · Physics 2016-11-03 Ben Moore

The formation of a singularity in a compressible gas, as described by the Euler equation, is characterized by the steepening, and eventual overturning of a wave. Using a self-similar description in two space dimensions, we show that the…

Fluid Dynamics · Physics 2017-05-24 J. Eggers , T. Grava , M. A. Herrada , G. Pitton

We prove that a flow of cold collisionless particles from all directions in and out of a region necessarily forms a caustic. A corollary is that, in cold dark matter cosmology, galactic halos have inner caustics in addition to the more…

Astrophysics · Physics 2009-11-13 Aravind Natarajan , Pierre Sikivie

Astronomical observations strongly suggest that our universe is now accelerating and contains a substantial admixture of dark vacuum energy. Using numerical simulations to study this newly consolidated cosmological model (with a constant…

Astrophysics · Physics 2009-11-10 Fred C. Adams , Michael T. Busha , August E. Evrard , Risa H. Wechsler

Dark matter caustics have specific density profiles and, therefore, precisely calculable gravitational lensing properties. We present a formalism which simplifies the relevant calculations, and apply it to four specific cases. In the first…

Astrophysics · Physics 2009-11-07 C. Charmousis , V. Onemli , Z. Qiu , P. Sikivie

We show that most particle and subhalo orbits in simulated cosmological cold dark matter halos are surprisingly regular and periodic: The phase space structure of the outer halo regions shares some of the properties of the classical…

Astrophysics · Physics 2009-11-13 J. Diemand , M. Kuhlen

We numerically investigate the long--time evolution of density perturbations after the first appearance of caustics in an expanding cosmological model with one--dimensional `single--wave' initial conditions. Focussing on the time--intervals…

Astrophysics · Physics 2007-05-23 Taihei Yano , Hiroko Koyama , Thomas Buchert , Naoteru Gouda

A better understanding of the formation of large-scale structure in the Universe is arguably the most pressing question in cosmology. The most compelling and promising theoretical paradigm, Inflation + Cold Dark Matter, holds that the…

Astrophysics · Physics 2009-10-30 Michael S. Turner

Theory and observations reveal fatal flaws in the standard LambdaCDM model. The cold dark matter hierarchical clustering paradigm predicts a gradual bottom-up growth of gravitational structures assuming linear, collisionless, ideal flows…

Astrophysics · Physics 2009-09-16 C. H. Gibson , T. M. Nieuwenhuizen , R. E. Schild