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Recent research has emphasized the benefits of accurately reconstructing the initial Lagrangian positions of biased tracers from their positions at a later time, to gain cosmological information. A weighted semi-discrete optimal transport…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-10 Farnik Nikakhtar , Nikhil Padmanabhan , Bruno Lévy , Ravi K. Sheth , Roya Mohayaee

The Vlasov-Poisson system, modeling the evolution of non-collisional plasmas in the electrostatic limit, is approx- imated by a Semi-Lagrangian technique. Spectral methods of periodic type are implemented through a collocation approach.…

Numerical Analysis · Mathematics 2019-03-27 Lorella Fatone , Daniele Funaro , Gianmarco Manzini

We present a test to quantify how well some approximate methods, designed to reproduce the mildly non-linear evolution of perturbations, are able to reproduce the clustering of DM halos once the grouping of particles into halos is defined…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-09 Emiliano Munari , Pierluigi Monaco , Jun Koda , Francisco-Shu Kitaura , Emiliano Sefusatti , Stefano Borgani

The dark matter halos that host galaxies and clusters form out of initial high-density patches, providing a biased tracer of the linear matter density field. In the simplest local bias approximation, the halo field is treated as a…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-15 Titouan Lazeyras , Marcello Musso , Vincent Desjacques

We investigate how unified models should be built to be able to predict the matter-density bispectrum (and power spectrum) from very large to small scales and that are at the same time consistent with perturbation theory at low $k$ and with…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Patrick Valageas , Takahiro Nishimichi

We propose a new method to linearise cosmological mass density fields using higher order Lagrangian perturbation theory (LPT). We demonstrate that a given density field can be expressed as the sum of a linear and a nonlinear component which…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 F. S. Kitaura , R. E. Angulo

We present results showing an improvement of the accuracy of perturbation theory as applied to cosmological structure formation for a useful range of quasilinear scales. The Lagrangian theory of gravitational instability of an Einstein-de…

Astrophysics · Physics 2007-05-23 T. Buchert , A. L. Melott , A. G. Weiss

We apply the convolved Lagrangian perturbation theory (CLPT) formalism, in which one can express the matter density power spectrum in terms of integrals over a function of cumulants of the displacement field, allowing for a resummation of…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-14 Zvonimir Vlah , Uroš Seljak , Tobias Baldauf

Accurate modeling of nonlinearities in the galaxy bispectrum, the Fourier transform of the galaxy three-point correlation function, is essential to fully exploit it as a cosmological probe. In this paper, we present numerical and…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-02 Nuala McCullagh , Donghui Jeong , Alexander S. Szalay

In this paper, we propose an inexact perturbed path-following algorithm in the framework of Lagrangian dual decomposition for solving large-scale structured convex optimization problems. Unlike the exact versions considered in literature,…

Optimization and Control · Mathematics 2011-09-16 Quoc Tran Dinh , Ion Necoara , Carlo Savorgnan , Moritz Diehl

Local-type primordial non-Gaussianity (PNG), predicted by many non-minimal models of inflation, creates a scale-dependent contribution to the power spectrum of large-scale structure (LSS) tracers. Its amplitude is characterized by the…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-03 Boryana Hadzhiyska , Simone Ferraro

We examine the Lagrangian divergence of the displacement field, arguably a more natural object than the density in a Lagrangian description of cosmological large-scale structure. This quantity, which we denote \psi, quantifies the…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-17 Mark C. Neyrinck

Associating the formation sites of haloes with the maxima of the smoothed linear density field, we present non-perturbative predictions for the Lagrangian and evolved halo correlation functions that are valid at all separations. In…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-05 Tobias Baldauf , Sandrine Codis , Vincent Desjacques , Christophe Pichon

Pre-trained Transformer-based models have achieved state-of-the-art performance for various Natural Language Processing (NLP) tasks. However, these models often have billions of parameters, and, thus, are too resource-hungry and…

Machine Learning · Computer Science 2021-09-29 Prakhar Ganesh , Yao Chen , Xin Lou , Mohammad Ali Khan , Yin Yang , Hassan Sajjad , Preslav Nakov , Deming Chen , Marianne Winslett

We present an enhanced version of the parametric nonlinear reduced order model for shape imperfections in structural dynamics we studied in a previous work [1]. The model is computed intrusively and with no training using information about…

Computational Engineering, Finance, and Science · Computer Science 2022-01-02 Jacopo Marconi , Paolo Tiso , Davide E. Quadrelli , Francesco Braghin

We update the ingredients of the Gaussian streaming model (GSM) for the redshift-space clustering of biased tracers using the techniques of Lagrangian perturbation theory, effective field theory (EFT) and a generalized Lagrangian bias…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-14 Zvonimir Vlah , Emanuele Castorina , Martin White

Approximations to the exact solutions for gravitational instability in the expanding Universe are extremely useful for understanding the evolution of large--scale structure. We report on a series of tests of Newtonian Lagrangian…

Astrophysics · Physics 2007-05-23 T. Buchert , A. L. Melott , A. G. Weiss

We extend the scale-dependent Gaussian Streaming Model (GSM) to produce analytical predictions for the anisotropic redshift-space correlation function for biased tracers in modified gravity models. Employing the Convolution Lagrangian…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-03 Georgios Valogiannis , Rachel Bean , Alejandro Aviles

We investigate the possible accuracy that can be reached by analytical models for the matter density power spectrum and correlation function. Using a realistic description of the power spectrum that combines perturbation theory with a halo…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-17 Patrick Valageas

We study the matter bispectrum of the large-scale structure by comparing different perturbative and phenomenological models with measurements from $N$-body simulations obtained with a modal bispectrum estimator. Using shape and amplitude…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-27 Andrei Lazanu , Tommaso Giannantonio , Marcel Schmittfull , E. P. S. Shellard