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We investigate a cosmological scenario in which the dark matter particles can be created during the evolution of the Universe. By regarding the Universe as an open thermodynamic system and using non-equilibrium thermodynamics, we examine…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-20 Z. Safari , K. Rezazadeh , B. Malekolkalami

We present results for the cosmic non-linear density-fluctuation power spectrum based on the analytical formalism developed in [1] which allows us to study cosmic structure formation based on Newtonian particle dynamics in phase-space. This…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-22 Tristan Daus , Elena Kozlikin

Matter evolved under influence of gravity from minuscule density fluctuations. Non-perturbative structure formed hierarchically over all scales, and developed non-Gaussian features in the Universe, known as the Cosmic Web. To fully…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-01 Siyu He , Yin Li , Yu Feng , Shirley Ho , Siamak Ravanbakhsh , Wei Chen , Barnabás Póczos

We reconsider the problem of gravitational structure formation inside and outside General Relativity (GR), both in the weakly and strongly non-linear regime. We show how these regimes can be explored observationally through clustering of…

Astrophysics · Physics 2009-10-31 Enrique Gaztanaga , Alberto Lobo

We present recent improvements in the perturbative treatment of particle interactions in Kinetic Field Theory (KFT) for inertial Zel'dovich trajectories. KFT has been developed for the systematic analytical calculation of non-linear cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-28 Christophe Pixius , Safak Celik , Matthias Bartelmann

Building upon the recent pioneering work by Mazenko and by Das and Mazenko, we develop a microscopic, non-equilibrium, statistical field theory for initially correlated canonical ensembles of classical microscopic particles obeying…

Statistical Mechanics · Physics 2019-04-08 Matthias Bartelmann , Felix Fabis , Daniel Berg , Elena Kozlikin , Robert Lilow , Celia Viermann

We develop a new perturbation theory (PT) treatment that can describe gravitational dynamics of large-scale structure after shell-crossing in the one-dimensional cosmological case. Starting with cold initial conditions, the motion of matter…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-02 Atsushi Taruya , Stéphane Colombi

We show how to simulate the clustering of rich clusters of galaxies using a technique based on the Zel'dovich approximation. This method well reproduces the spatial distribution of clusters obtainable from full N-body simulations at a…

Astrophysics · Physics 2015-06-24 S. Borgani , P. Coles , L. Moscardini

Non-linear gravitational clustering in a universe dominated by dark energy, modelled by a `quintessence' scalar field, and cold dark matter with space-time varying mass is studied. Models of this type, where the variable mass is induced by…

Astrophysics · Physics 2009-11-07 S. Matarrese , M. Pietroni , C. Schimd

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

Modern sky surveys are returning precision measurements of cosmological statistics such as weak lensing shear correlations, the distribution of galaxies, and cluster abundance. To fully exploit these observations, theorists must provide…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Katrin Heitmann , Earl Lawrence , Juliana Kwan , Salman Habib , David Higdon

Nonlinear effects are crucial in order to compute the cosmological matter power spectrum to the accuracy required by future generation surveys. Here, a new approach is presented, in which the power spectrum, the bispectrum and higher order…

Astrophysics · Physics 2009-11-13 Massimo Pietroni

The adhesion model has been proposed in the past as an improvement of the Zel'dovich approximation, providing a good description of the formation of the cosmic web. We recast the model as a field theory for cosmological large scale…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Gerasimos Rigopoulos

We present a simple and intuitive approximation for solving perturbation theory (PT) of small cosmic fluctuations. We consider only the spherically symmetric or monopole contribution to the PT integrals, which yields the exact result for…

Astrophysics · Physics 2009-10-30 P. Fosalba , E. Gaztanaga

This Report discusses a recently developed concept of Limiting Phase Trajectories (LPTs) providing a unified description of resonant energy transport in a wide range of classical and quantum dynamical systems with constant and time-varying…

Pattern Formation and Solitons · Physics 2016-05-31 Leonid Manevitch , Agnessa Kovaleva , Yuli Starosvetsky

The next generation of cosmological surveys will operate over unprecedented scales, and will therefore provide exciting new opportunities for testing general relativity. The standard method for modelling the structures that these surveys…

General Relativity and Quantum Cosmology · Physics 2018-03-28 Sophia R. Goldberg , Christopher Gallagher , Timothy Clifton

Constraining cosmological parameters from large-scale structure observations requires precise and accurate tools to compute its properties. While perturbation theory (PT) approaches can serve this purpose, exploration of large parameter…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-12 Ken Osato , Takahiro Nishimichi , Atsushi Taruya , Francis Bernardeau

We study the geometry and topology of the large-scale structure traced by galaxy clusters in numerical simulations of a box of side 320 $h^{-1}$ Mpc, and compare them with available data on real clusters. The simulations we use are…

Astrophysics · Physics 2020-11-25 P. Coles , R. C. Pearson , S. Borgani , M. Plionis , L. Moscardini

The growth of large-scale structure, together with the geometrical information of cosmic expansion history and cosmological distances, can be used to obtain constraints on the spatial curvature of the universe that probes the early universe…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-23 Ryo Terasawa , Ryuichi Takahashi , Takahiro Nishimichi , Masahiro Takada

We investigate cosmic structure formation in the framework of a path-integral formulation of an $N$-particle ensemble in phase space, dubbed Resummed Kinetic Field Theory (RKFT), up to one-loop perturbative order. In particular, we compute…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-11 Marvin Sipp , Hannes Heisler , Matthias Bartelmann