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An $f(R)$ gravity model is proposed to realize a late time accelerated expansion of our Universe. To test the viability of an $f(R)$ gravity model through cosmic observations, the background evolution and the Einstein-Boltzmann equation…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Lixin Xu

The Planck experiment has measured the Cosmic Microwave Background (CMB) angular spectrum with unprecedented accuracy, and these results are likely to remain the state-of-the art for a decade or more. Since these measurements are going to…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-17 Julia Stadler , Céline Bœhm

Line-intensity mapping (LIM) provides a promising way to probe cosmology, reionization and galaxy evolution. However, its sensitivity to cosmology and astrophysics at the same time is also a nuisance. Here we develop a comprehensive…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-21 José Luis Bernal , Patrick C. Breysse , Héctor Gil-Marín , Ely D. Kovetz

We apply the microscopic coupled-cluster method (CCM) to the spin-$1\over2$ $XXZ$ models on both the one-dimensional chain and the two-dimensional square lattice. Based on a systematic approximation scheme of the CCM developed by us…

Condensed Matter · Physics 2017-08-24 R. F. Bishop , R. G. Hale , Y. Xian

The Boltzmann equation has been a driving force behind significant mathematical research over the years. Its challenging theoretical complexity, combined with a wide variety of current scientific and technological problems that require…

Mathematical Physics · Physics 2026-03-11 Liliane Basso Barichello

In this paper we analyse the alignment of galaxy groups with the surrounding large scale structure traced by spectroscopic galaxies from the Sloan Digital Sky Survey Data Release 7. We characterise these alignments by means of an extension…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Dante J. Paz , Mario A. Sgró , Manuel Merchán , Nelson Padilla

Restricted Boltzmann machines (RBMs) are powerful machine learning models, but learning and some kinds of inference in the model require sampling-based approximations, which, in classical digital computers, are implemented using expensive…

Machine Learning · Statistics 2014-10-27 Vincent Dumoulin , Ian J. Goodfellow , Aaron Courville , Yoshua Bengio

We propose a novel approach for parameterizing the luminosity distance, based on the use of rational "Pad\'e" approximations. This new technique extends standard Taylor treatments, overcoming possible convergence issues at high redshifts…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Alejandro Aviles , Alessandro Bravetti , Salvatore Capozziello , Orlando Luongo

BosonSampling is a restricted model of quantum computation proposed recently, where a non-adaptive linear-optical network is used to solve a sampling problem that seems to be hard for classical computers. Here we show that, even if the…

Quantum Physics · Physics 2015-04-22 Daniel J. Brod

The multi-scale nature of gaseous flows poses tremendous difficulties for theoretical and numerical analysis. The Boltzmann equation, while possessing a wider applicability than hydrodynamic equations, requires significantly more…

Fluid Dynamics · Physics 2023-07-19 Tianbai Xiao , Steffen Schotthöfer , Martin Frank

Initial conditions for (Newtonian) cosmological N-body simulations are usually set by re-scaling the present-day power spectrum obtained from linear (relativistic) Boltzmann codes to the desired initial redshift of the simulation. This…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-28 Christian Fidler , Thomas Tram , Cornelius Rampf , Robert Crittenden , Kazuya Koyama , David Wands

We are now beginning to learn detailed information about cosmological parameters from the shapes of the matter and radiation power spectra, together with their relative normalization. As more high quality data are gathered from galaxy…

Astrophysics · Physics 2007-05-23 Douglas Scott

The recent measurements of the power spectrum of Cosmic Microwave Background anisotropies are consistent with the simplest inflationary scenario and big bang nucleosynthesis constraints. However, these results rely on the assumption of a…

A recently proposed Asymptotically Safe cosmology provides an elegant mechanism towards understanding the nature of dark energy and its associated cosmic coincidence problem. The underlying idea is that the accelerated expansion of the…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-06 Fotios K. Anagnostopoulos , Spyros Basilakos , Georgios Kofinas , Vasilios Zarikas

We present efficient algorithms to calculate trajectories for periodic Lorentz gases consisting of square lattices of circular obstacles in two dimensions, and simple cubic lattices of spheres in three dimensions; these become increasingly…

Chaotic Dynamics · Physics 2016-01-20 Atahualpa S. Kraemer , Nikolay Kryukov , David P. Sanders

Entropic lattice Boltzmann methods have been developed to alleviate intrinsic stability issues of lattice Boltzmann models for under-resolved simulations. Its reliability in combination with moving objects was established for various…

Fluid Dynamics · Physics 2017-06-21 B. Dorschner , S. S. Chikatamarla , I. V. Karlin

Cosmic microwave background (CMB) anisotropies and density fluctuations are calculated for flat cold dark matter (CDM) models with a wide range of parameters, i.e., $\Omega_0, h$ and $\Omega_B$ for both standard recombination and various…

Astrophysics · Physics 2009-10-22 Naoshi Sugiyama

Cosmography is a powerful tool to investigate the Universe kinematic and then to reconstruct dynamics in a model-independent way. However, recent new measurements of supernovae Ia and quasars have populated the Hubble diagram up to high…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-19 Giada Bargiacchi , G. Risaliti , M. Benetti , S. Capozziello , E. Lusso , A. Saccardi , M. Signorini

Models of relativistic heavy ion collisions typically involve both a hydrodynamic module to describe the high density liquid-like phase and a Boltzmann module to simulate the low density break-up phase which is gas-like. Coupling the…

Nuclear Theory · Physics 2010-10-27 Scott Pratt , Giorgio Torrieri

Cosmography is a widely applied method to infer kinematics of the Universe at small cosmological scales while remaining agnostic about the theory of gravity at play. Usually cosmologists invoke the Friedmann-Lemaitre-Robertson-Walker (FLRW)…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-25 Hayley J. Macpherson , Asta Heinesen
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