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Reconstructing cosmological initial conditions (ICs) from late-time observations is a difficult task, which relies on the use of computationally expensive simulators alongside sophisticated statistical methods to navigate multi-million…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-22 Oleg Savchenko , Florian List , Guillermo Franco Abellán , Noemi Anau Montel , Christoph Weniger

In this work we investigate the nonlinear and nonlocal relation between cosmological density and peculiar velocity fields. Our goal is to provide an algorithm for the recon- struction of the nonlinear velocity field from the fully nonlinear…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Francisco-Shu Kitaura , Raul E. Angulo , Yehuda Hoffman , Stefan Gottl"ober

We present the one-loop 2-point function of biased tracers in redshift space computed with Lagrangian perturbation theory, including a full resummation of both long-wavelength (infrared) displacements and associated velocities. The…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-14 Shi-Fan Chen , Zvonimir Vlah , Emanuele Castorina , Martin White

We show how gauge-invariant cosmological perturbations may be constructed by an unambiguous choice of hypersurface-orthogonal time-like vector field (i.e., time-slicing). This may be defined either in terms of the metric quantities such as…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Karim A. Malik , David Wands

This chapter is a non-expert introduction to the effective field theory of large scale structure. First, we give a detailed pedagogical explanation of why previous attempts to build non-linear cosmological perturbation theory failed. After…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-19 Mikhail M. Ivanov

An implicit fundamental assumption in relativistic perturbation theory is that there exists a parametric family of spacetimes that can be Taylor expanded around a background. The choice of the latter is crucial to obtain a manageable…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Marco Bruni , Leonardo Gualtieri , Carlos F. Sopuerta

We investigate the information on cosmology contained in Gaussianised weak gravitational lensing convergence fields. Employing Box-Cox transformations to determine optimal transformations to Gaussianity, we develop analytical models for the…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 B. Joachimi , A. N. Taylor , A. Kiessling

We consider a cosmological model with non-Gaussian initial perturbations, which in principle could be generated in non-standard inflationary scenarios with two or more scalar fields. In particular we focus our attention on the model…

Astrophysics · Physics 2011-05-10 Dmitri Novikov , Jens Schmalzing , Viatcheslav F. Mukhanov

It is shown that a first-order cosmological perturbation theory for the open, flat and closed Friedmann-Lema\^itre-Robertson-Walker universes admits one, and only one, gauge-invariant variable which describes the perturbation to the energy…

General Relativity and Quantum Cosmology · Physics 2014-10-02 P. G. Miedema , W. A. van Leeuwen

We have previously reported a Bayesian algorithm for determining the coordinates of points in three-dimensional space from uncertain constraints. This method is useful in the determination of biological molecular structure. It is limited,…

Artificial Intelligence · Computer Science 2013-02-28 Russ B. Altman , Cheng C. Chen , William B. Poland , Jaswinder Pal Singh

Random fields are useful mathematical tools for representing natural phenomena with complex dependence structures in space and/or time. In particular, the Gaussian random field is commonly used due to its attractive properties and…

Inspired by the fully non-linear Geodesic Light-Cone (GLC) gauge, we consider its analogous set of coordinates which describes the unperturbed Universe. Given this starting point, we then build a cosmological perturbation theory on top of…

General Relativity and Quantum Cosmology · Physics 2021-02-15 Giuseppe Fanizza , Giovanni Marozzi , Matheus Medeiros , Gloria Schiaffino

We present a multivariate Gaussian process regression approach for parameter field reconstruction based on the field's measurements collected at two different scales, the coarse and fine scales. The proposed approach treats the parameter…

Methodology · Statistics 2018-04-19 David A. Barajas-Solano , Alexandre M. Tartakovsky

Multimode Gaussian states are a versatile resource for quantum information technologies and have been realized across a wide range of physical platforms. Recent progress in the large-scale generation of such states provides a key ingredient…

Quantum Physics · Physics 2026-04-14 Chan Roh , Geunhee Gwak , Young-Do Yoon , Young-Sik Ra

Perturbations in a universe with matter and cosmological constant are computed in terms of the primordial scalar perturbation up to second order. The calculation is easy -- a generalization of the spherical dust solution. Our expression…

Astrophysics · Physics 2007-05-23 Andrei Gruzinov

Bayesian field theory denotes a nonparametric Bayesian approach for learning functions from observational data. Based on the principles of Bayesian statistics, a particular Bayesian field theory is defined by combining two models: a…

Data Analysis, Statistics and Probability · Physics 2007-05-23 J. C. Lemm

We investigate how the consistency relations of large-scale structures are modified when the initial density field is not Gaussian. We consider both scenarios where the primordial density field can be written as a nonlinear functional of a…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-22 Patrick Valageas , Atsushi Taruya , Takahiro Nishimichi

Low-dose tomography is highly preferred in medical procedures for its reduced radiation risk when compared to standard-dose Computed Tomography (CT). However, the lower the intensity of X-rays, the higher the acquisition noise and hence the…

Image and Video Processing · Electrical Eng. & Systems 2019-12-24 Preeti Gopal , Sharat Chandran , Imants Svalbe , Ajit Rajwade

We treat an image restoration problem with a Poisson noise chan- nel using a Bayesian framework. The Poisson randomness might be appeared in observation of low contrast object in the field of imaging. The noise observation is often hard to…

Computer Vision and Pattern Recognition · Computer Science 2014-12-09 Hayaru Shouno

Smoothing operation to make continuous density field from observed point-like distribution of galaxies is crucially important for topological or morphological analysis of the large-scale structure, such as, the genus statistics or the area…

Astrophysics · Physics 2016-08-30 Naoki Seto