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Dark energy (DE) plays an important role in the expansion history of our universe. But we only got limited knowledge about its nature and properties after decades of study.In most numerical researches, DE is usually considered as a…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-02 Ke Wang , Lu Chen

Neural Ordinary Differential Equations (NODEs) have proven to be a powerful modeling tool for approximating (interpolation) and forecasting (extrapolation) irregularly sampled time series data. However, their performance degrades…

Machine Learning · Computer Science 2020-04-29 Hammad A. Ayyubi , Yi Yao , Ajay Divakaran

Near-future cosmological observations targeted at investigations of dark energy pose stringent requirements on the accuracy of theoretical predictions for the clustering of matter. Currently, N-body simulations comprise the only viable…

Astrophysics · Physics 2010-08-25 Katrin Heitmann , Martin White , Christian Wagner , Salman Habib , David Higdon

We study the dynamics of expansion of the homogeneous isotropic Universe and the evolution of its components in the model with nonminimally coupled dynamical dark energy. Dark energy, like the other components of the Universe, is described…

General Relativity and Quantum Cosmology · Physics 2017-12-05 R. Neomenko , B. Novosyadlyj , O. Sergijenko

We compute the decay spectrum for dark matter (DM) with masses above the scale of electroweak symmetry breaking, all the way to the Planck scale. For an arbitrary hard process involving a decay to the unbroken standard model, we determine…

High Energy Physics - Phenomenology · Physics 2021-07-07 Christian W. Bauer , Nicholas L. Rodd , Bryan R. Webber

We present the first attempt to analytically study the nonlinear matter power spectrum for a mixed dark matter (cold dark matter plus neutrinos of total mass ~0.1eV) model based on cosmological perturbation theory. The suppression in the…

Astrophysics · Physics 2009-06-23 Shun Saito , Masahiro Takada , Atsushi Taruya

We describe a novel end-to-end approach using Machine Learning to reconstruct the power spectrum of cosmological density perturbations at high redshift from observed quasar spectra. State-of-the-art cosmological simulations of structure…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-21 Maria Han Veiga , Xi Meng , Oleg Y. Gnedin , Nickolay Y. Gnedin , Xun Huan

We put constraints on dark energy properties using the PADE parameterisation, and compare it to the same constraints using Chevalier-Polarski-Linder (CPL) and $\Lambda$CDM, at both the background and the perturbation levels. The dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-09 Mehdi Rezaei , Mohammad Malekjani , Spyros Basilakos , Ahmad Mehrabi , David F. Mota

We investigate the non-linear evolution of the matter power spectrum by using a large set of high-resolution N-body/hydrodynamic simulations. The linear matter power in the initial conditions is consistently modified to accommodate warm…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Matteo Viel , Katarina Markovic , Marco Baldi , Jochen Weller

According to the Harrison-Zel'dovich prescription, the amplitude of matter density perturbations at horizon crossing is the same at all scales. Based on this prescription, we show how to construct the matter power spectrum of generic dark…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Iván Durán , Fernando Atrio-Barandela , Diego Pavón

We consider a 12-parameter cosmological model with non-phantom dynamical dark energy (NPDDE), where non-phantom implies that the equation of state (EoS) of dark energy (DE), $w(z)\geq-1$ for all redshifts $z$. Thus, the DE EoS covers the…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-20 Shouvik Roy Choudhury , Teppei Okumura , Keiichi Umetsu

Dark energy, the enigmatic force driving the accelerated cosmic expansion of the universe, is conventionally described as a cosmological constant in the standard $\Lambda$CDM model. However, measurements from the Dark Energy Spectroscopic…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-26 Axel de la Macorra , Jose Agustin Lozano Torres

The next generation mass probes will obtain information on non--linear power spectra P(k,z) and their evolution, allowing us to investigate the nature of Dark Energy. To exploit such data we need high precision simulations, extending at…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Luciano Casarini , Andrea V. Maccio' , Silvio A. Bonometto , Greg S. Stinson

Given a class of dark energy models, constraints from one set of cosmic acceleration observables make predictions for other observables. Here we present the allowed ranges for the expansion rate H(z), distances D(z), and the linear growth…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-23 Michael J. Mortonson , Wayne Hu , Dragan Huterer

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

We study the nonlinear regime of large scale structure formation considering a dynamical dark energy (DE) component determined by a Steep Equation of State parametrization (SEoS) $w(z)=w_0+w_i\frac{(z/z_T)^q}{1+(z/z_T)^q}$. In order to…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 N. Chandrachani Devi , M. Jaber-Bravo , G. Aguilar-Argüello , O. Valenzuela , A. de la Macorra , H. Velázquez

Hamilton et al. have suggested an invaluable scaling formula which describes how the power spectra of density fluctuations evolve into the nonlinear regime of hierarchical clustering. This paper presents an extension of their method to…

Astrophysics · Physics 2016-06-08 J. A. Peacock , S. J. Dodds

We allow for nonlinear effects in the likelihood analysis of galaxy peculiar velocities, and obtain ~35%-lower values for the cosmological density parameter Om and the amplitude of mass-density fluctuations. The power spectrum in the linear…

Astrophysics · Physics 2009-11-06 L. Silberman , A. Dekel , A. Eldar , I. Zehavi

We study the late-time evolution of the Universe where dark energy (DE) is presented by a barotropic fluid on top of cold dark matter (CDM). We also take into account the radiation content of the Universe. Here by the late stage of the…

General Relativity and Quantum Cosmology · Physics 2015-07-24 Ozgur Akarsu , Mariam Bouhmadi-López , Maxim Brilenkov , Ruslan Brilenkov , Maxim Eingorn , Alexander Zhuk

To effectively exploit large-scale structure surveys, we depend on accurate and reliable predictions of non-linear cosmological structure formation. Tools for efficient and comprehensive computational modelling are therefore essential to…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 Benjamin Bose , Matteo Cataneo , Tilman Tröster , Qianli Xia , Catherine Heymans , Lucas Lombriser