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We investigate the perturbative integrability of different quantum field theories in 1+1 dimensions at one loop. Starting from massive bosonic Lagrangians with polynomial-like potentials and absence of inelastic processes at the tree level,…

High Energy Physics - Theory · Physics 2023-04-26 Davide Polvara

The k-d tree was one of the first spatial data structures proposed for nearest neighbor search. Its efficacy is diminished in high-dimensional spaces, but several variants, with randomization and overlapping cells, have proved to be…

Data Structures and Algorithms · Computer Science 2013-02-11 Sanjoy Dasgupta , Kaushik Sinha

We consider the growth of primordial dark matter halos seeded by three crossed initial sine waves of various amplitudes. Using a Lagrangian treatment of cosmological gravitational dynamics, we examine the convergence properties of a…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-18 Shohei Saga , Atsushi Taruya , Stéphane Colombi

We study graph estimation and density estimation in high dimensions, using a family of density estimators based on forest structured undirected graphical models. For density estimation, we do not assume the true distribution corresponds to…

Machine Learning · Statistics 2010-10-21 Han Liu , Min Xu , Haijie Gu , Anupam Gupta , John Lafferty , Larry Wasserman

We present predictions for the one-point probability distribution and cumulants of the transmitted QSO flux in the high redshift Lyman-$\alpha$ Forest. We make use of the correlation between the Lyman-$\alpha$ optical depth and the…

Astrophysics · Physics 2009-10-31 Enrique Gaztanaga , Rupert A. C. Croft

We develop perturbation theory approaches to model the marked correlation function constructed to up-weight low density regions of the Universe, which might help distinguish modified gravity models from the standard cosmology model based on…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-15 Alejandro Aviles , Kazuya Koyama , Jorge L. Cervantes-Cota , Hans A. Winther , Baojiu Li

To eliminate gravitational non-Gaussianity, we introduce the $\mathcal{Z}$-$\kappa$ transform, a simple local nonlinear transform of the matter density field that emulates the inverse of nonlinear gravitational evolution. Using $N$-body…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-16 Yun Wang , Hao-Ran Yu , Yu Yu , Ping He

We develop a non-perturbative method to derive the probability distribution $P(\delta_R)$ of the density contrast within spherical cells in the quasi-linear regime. Indeed, since this corresponds to a rare-event limit a steepest-descent…

Astrophysics · Physics 2009-11-06 P. Valageas

(Abridged) By comparing the frequency of typical events with that of unusual events, one can test whether the cosmological density distribution function is consistent with the normally made assumption of Gaussianity. To this end, we compare…

Astrophysics · Physics 2009-10-30 Weihsueh A. Chiu , Jeremiah P. Ostriker , Michael A. Strauss

The statistics of power fluctuations are studied in simulations of two-dimensional turbulence in both inverse (energy) and direct (enstrophy) cascade regimes from both Lagrangian and Eulerian perspectives. The probability density function…

Statistical Mechanics · Physics 2008-03-01 M. M. Bandi , C. Connaughton

Phylogenetic trees constitute an interesting class of objects for stochastic processes due to the non-standard nature of the space they inhabit. In particular, many statistical applications require the construction of Markov processes on…

Probability · Mathematics 2024-10-24 Rodrigo B. Alves , Yuri F. Saporito , Luiz M. Carvalho

We introduce a Lagrangian-space Effective Field Theory (LEFT) formalism for the study of cosmological large scale structures. Unlike the previous Eulerian-space construction, it is naturally formulated as an effective field theory of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Rafael A. Porto , Leonardo Senatore , Matias Zaldarriaga

Inhomogeneities in real-world data, e.g., due to changes in the observation noise level or variations in the structural complexity of the source function, pose a unique set of challenges for statistical inference. Accounting for them can…

Machine Learning · Computer Science 2023-12-13 Danny Panknin , Stefan Chmiela , Klaus-Robert Müller , Shinichi Nakajima

The bispectrum, the three-point function of density fluctuations in Fourier space, is the lowest order statistic that carries information about the spatial coherence of large-scale structures. For Gaussian initial conditions, when the…

Continuum fitting uncertainties are a major source of error in estimates of the temperature-density relation (usually parametrized as a power-law, $T \propto \Delta^{\gamma - 1} $) of the inter-galactic medium (IGM) through the flux…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-28 Khee-Gan Lee

We calculate the cosmological evolution of the 1-point probability distribution function (PDF), using an analytic approximation that combines gravitational perturbation theory with the Edgeworth expansion of the PDF. Our method applies…

Astrophysics · Physics 2009-10-22 R. Juszkiewicz , D. Weinberg , P. Amsterdamski , M. Chodorowski , F. Bouchet

There is a conformal equivalence between power law $f(R)$ theories and scalar field theories in which the scalar degree of freedom evolves under the action of an exponential potential function. In the scalar field representation there is a…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Yousef Bisabr

Many models of high energy physics suggest that the cosmological dark sector consists of not just one, but a spectrum of ultralight scalar particles with logarithmically distributed masses. To study the potential signatures of low…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-17 Alex Laguë , J. Richard Bond , Renée Hložek , David J. E. Marsh , Laurin Söding

We investigate the building of unified models that can predict the matter-density power spectrum and the two-point correlation function from very large to small scales, being consistent with perturbation theory at low $k$ and with halo…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Patrick Valageas , Takahiro Nishimichi

We consider the task of sampling with respect to a log concave probability distribution. The potential of the target distribution is assumed to be composite, \textit{i.e.}, written as the sum of a smooth convex term, and a nonsmooth convex…

Machine Learning · Statistics 2021-02-23 Adil Salim , Peter Richtárik