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We present a method, based on the correlation function of excursion sets above a given threshold, to test the Gaussianity of the CMB temperature fluctuations in the sky. In particular, this method can be applied to discriminate between…

Astrophysics · Physics 2009-10-30 R. B. Barreiro , J. L. Sanz , E. Martinez-Gonzalez , J. Silk

We stress the importance of stochastic geometry as a branch of mathematical statistics particularly suited to model and investigate nontrivial spatial patterns. One of its key concepts, Voronoi tessellations, represents a versatile and…

Astrophysics · Physics 2007-05-23 Rien van de Weygaert

We investigate the existence and properties of equipotential surfaces and Lagrangian points in non-synchronous, eccentric binary star and planetary systems under the assumption of quasi-static equilibrium. We adopt a binary potential that…

Astrophysics · Physics 2011-02-11 J. F. Sepinsky , B. Willems , V. Kalogera

Consider a 2-plane $P \subset \mathbb{C}^n$ and let $D$ be a bounded region in $P$ with a piecewise-smooth boundary. Let $I(D)$ be the infimum of areas of all piecewise-smooth isotropic surfaces in $\mathbb{C}^n$ with the same boundary as…

Differential Geometry · Mathematics 2007-05-23 Edward Goldstein

The survey volume of a proper motion-limited sample is typically much smaller than a magnitude-limited sample. This is because of the noisy astrometric measurements from detectors that are not dedicated for astrometric missions. In order to…

Instrumentation and Methods for Astrophysics · Physics 2017-05-01 Marco C. Lam

We investigate fundamental localized modes in 2D lattices with an edge (surface). Interaction with the edge expands the stability area for ordinary solitons, and induces a difference between perpendicular and parallel dipoles; on the…

Pattern Formation and Solitons · Physics 2010-12-10 H. Susanto , P. G. Kevrekidis , B. A. Malomed , R. Carretero-Gonzalez , D. J. Frantzeskakis

We quantify the degree of nonlinearity and stochasticity of the clustering of biased objects, using cosmological N-body simulations. Adopting the peaks and the halos as representative biasing models, we focus on the two-point correlation of…

Astrophysics · Physics 2015-06-24 A. Taruya , H. Magira , Y. P. Jing , Y. Suto

We review and study some of the properties of smooth Gaussian random fields defined on a homogeneous space, under the assumption that the probability distribution is invariant under the isometry group of the space. We first give an…

Probability · Mathematics 2022-04-22 Alexandre Afgoustidis

In a quadruply imaged lens system the angular distribution of images around the lens center is completely described by three relative angles. We show empirically that in the 3D space of these angles, spanning 180 x 180 x 90 degrees, quads…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Addishiwot G. Woldesenbet , Liliya L. R. Williams

We describe a simple fully analytic model of the excursion set approach associated with two Gaussian random walks: the first walk represents the initial overdensity around a protohalo, and the second is a crude way of allowing for other…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Emanuele Castorina , Ravi K. Sheth

We consider a discrete-time continuous-space random walk under the constraints that the number of returns to the origin (local time) and the total area under the walk are fixed. We first compute the joint probability of an excursion having…

Statistical Mechanics · Physics 2016-12-13 Juraj Szavits-Nossan , Martin R. Evans , Satya N. Majumdar

We begin by studying the surface area of an ellipsoid in n-dimensional Euclidean space as the function of the lengths of the semi-axes. We write down an explicit formula as an integral over the unit sphere in n-dimensions and use this…

Metric Geometry · Mathematics 2007-05-23 Igor Rivin

The effective dilatational and shear viscosities of a particle-laden fluid interface are computed in the dilute limit under the assumption of an asymptotically vanishing viscosity ratio between both fluids. Spherical particles with a given…

Fluid Dynamics · Physics 2020-10-28 Michael Eigenbrod , Steffen Hardt

We prove an exact trace formula for the Laplacian with a delta potential - also known as a point scatterer - on a non-compact hyperbolic surface of finite volume with one cusp. Our formula is an analogue of the Selberg trace formula. We…

Mathematical Physics · Physics 2012-03-12 Henrik Ueberschaer

We investigate the percolation transition of aligned, overlapping, anisotropic shapes on lattices. Using the recently proposed lattice version of excluded volume theory, we show that shape-anisotropy leads to some intriguing consequences…

Statistical Mechanics · Physics 2025-01-13 Jasna C. K. , V. Sasidevan

Levy flights are random walks in which the probability distribution of the step sizes is fat-tailed. Levy spatial diffusion has been observed for a collection of ultra-cold Rb atoms and single Mg+ ions in an optical lattice. Using the…

Statistical Mechanics · Physics 2015-07-28 E. Barkai , E. Aghion , D. A. Kessler

We analyse and improve the volume-penalty method, a simple and versatile way to model objects in fluid flows. The volume-penalty method is a kind of fictitious-domain method that approximates no-slip boundary conditions with rapid linear…

Numerical Analysis · Mathematics 2020-12-09 Eric W. Hester , Geoffrey M. Vasil , Keaton J. Burns

We give a method for computing upper and lower bounds for the volume of a non-obtuse hyperbolic polyhedron in terms of the combinatorics of the 1-skeleton. We introduce an algorithm that detects the geometric decomposition of good…

Geometric Topology · Mathematics 2012-11-22 Christopher K. Atkinson

Visual odometry techniques typically rely on feature extraction from a sequence of images and subsequent computation of optical flow. This point-to-point correspondence between two consecutive frames can be costly to compute and suffers…

Computer Vision and Pattern Recognition · Computer Science 2025-12-02 Chenqi Zhu , Levi Burner , Yiannis Aloimonos

This article gives the construction and complete classification of all three-dimensional spherical manifolds, and orders them by decreasing volume, in the context of multiconnected universe models with positive spatial curvature. It…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Evelise Gausmann , Roland Lehoucq , Jean-Pierre Luminet , Jean-Philippe Uzan , Jeffrey Weeks