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We present a new method to compute the first crossing distribution in excursion set theory for the case of correlated random walks. We use a combination of the path integral formalism of Maggiore & Riotto, and the integral equation solution…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-18 Arya Farahi , Andrew J. Benson

We study the effects of primordial non-Gaussianity on the large scale structure in the excursion set approach, accounting for correlations between steps of the random walks in the smoothed initial density field. These correlations are…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-23 Marcello Musso , Aseem Paranjape

Recently, we provided a simple but accurate formula which closely approximates the first crossing distribution associated with random walks having correlated steps. The approximation is accurate for the wide range of barrier shapes of…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-09 Marcello Musso , Ravi K. Sheth

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

The excursion set approach is a framework for estimating how the number density of nonlinear structures in the cosmic web depends on the expansion history of the universe and the nature of gravity. A key part of the approach is the…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-31 Farnik Nikakhtar , Mohammadreza Ayromlou , Shant Baghram , Sohrab Rahvar , M. Reza Rahimi Tabar , Ravi K. Sheth

We provide a simple formula that accurately approximates the first crossing distribution of barriers having a wide variety of shapes, by random walks with a wide range of correlations between steps. Special cases of it are useful for…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-25 Marcello Musso , Ravi K. Sheth

The excursion set theory, where density perturbations evolve stochastically with the smoothing scale, provides a method for computing the dark matter halo mass function. The computation of the mass function is mapped into the so-called…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-05 Andrea De Simone , Michele Maggiore , Antonio Riotto

Random walks with a general, nonlinear barrier have found recent applications ranging from reionization topology to refinements in the excursion set theory of halos. Here, we derive the first-crossing distribution of random walks with a…

Astrophysics · Physics 2009-11-13 Jun Zhang , Lam Hui

The simplest stochastic halo formation models assume that the traceless part of the shear field acts to increase the initial overdensity (or decrease the underdensity) that a protohalo (or protovoid) must have if it is to form by the…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-09 Marcello Musso , Ravi K. Sheth

Excursion set theory, where density perturbations evolve stochastically with the smoothing scale, provides a method for computing the mass function of cosmological structures like dark matter halos, sheets and filaments. The computation of…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-28 Andrea De Simone , Michele Maggiore , Antonio Riotto

Primordial non-Gaussianity (NG) affects the large scale structure (LSS) of the universe by leaving an imprint on the distribution of matter at late times. Much attention has been focused on using the distribution of collapsed objects (i.e.…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-25 Guido D'Amico , Marcello Musso , Jorge Noreña , Aseem Paranjape

A classic method for computing the mass function of dark matter halos is provided by excursion set theory, where density perturbations evolve stochastically with the smoothing scale, and the problem of computing the probability of halo…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Michele Maggiore , Antonio Riotto

The excursion set approach uses the statistics of the density field smoothed on a wide range of scales, to gain insight into a number of interesting processes in nonlinear structure formation, such as cluster assembly, merging and…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-13 Marcello Musso , Ravi K. Sheth

Primordial non-Gaussianity is a potentially powerful discriminant of the physical mechanisms that generated the cosmological fluctuations observed today. Any detection of significant non-Gaussianity would thus have profound implications for…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-25 Vincent Desjacques , Uros Seljak

In this paper we consider the one-dimensional, biased, randomly trapped random walk when the trapping times have infinite variance. We prove sufficient conditions for the suitably scaled walk to converge to a transformation of a stable…

Probability · Mathematics 2026-01-14 Adam Bowditch

In recent years, several experiments highlighted a new type of diffusion anomaly, which was called Brownian yet non-Gaussian diffusion. In systems displaying this behavior, the mean squared displacement of the diffusing particles grows…

Statistical Mechanics · Physics 2023-08-01 Adrian Pacheco-Pozo , Igor M. Sokolov

In this work we establish a link between two different phenomena that were studied in a large and growing number of biological, composite and soft media: the diffusion in compartmentalized environment and the Brownian yet non-Gaussian…

Statistical Mechanics · Physics 2020-08-05 Jakub Ślęzak , Stanislav Burov

A sizeable level of non-Gaussianity in the primordial cosmological perturbations may be induced by a large trispectrum, i.e. by a large connected four-point correlation function. We compute the effect of a primordial non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Michele Maggiore , Antonio Riotto

Primordial non-Gaussianity is a potentially powerful discriminant of the physical mechanisms that generated the cosmological fluctuations observed today. Any detection of non-Gaussianity would have profound implications for our…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Vincent Desjacques , Uros Seljak

We investigate the fluctuations of the time elapsed until the electric charge transferred through a conductor reaches a given threshold value. For this purpose, we measure the distribution of the first-passage times for the net number of…

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