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We consider the problem of finding approximate analytical solutions for nonlinear equations typical of physics applications. The emphasis is on the modification of the method of Pad\'e approximants that are known to provide the best…

Mathematical Physics · Physics 2020-04-01 S. Gluzman , V. I. Yukalov

It is well known that rational approximation theory involves degenerate hypergeometric functions and, in particular, the Pad\'e approximation of the exponential function is closely related to Kummer hypergeometric functions. Recently, in…

Optimization and Control · Mathematics 2022-12-06 Islam Boussaada , Guilherme Mazanti , Silviu-Iulian Niculescu

Context. Gamma-ray bursts (GRBs) reach redshifts beyond Type Ia supernovae (SNe Ia) and can extend distance measurements into the early Universe, but their use as distance indicators is limited by the circularity problem in calibrating…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-19 Wei Hong , Luca Izzo , Massimo Della Valle , Orlando Luongo , Marco Muccino , Tong-Jie Zhang

The concordance (LambdaCDM) model reproduces the main current cosmological observations assuming the validity of general relativity at all scales and epochs, the presence of cold dark matter, and of a cosmological constant, equivalent to a…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-08 Guido Risaliti , Elisabeta Lusso

We use cosmography to present constraints on the kinematics of the Universe without postulating any underlying theoretical model a priori. To this end, we use a Markov Chain Monte Carlo analysis to perform comparisons to the supernova Ia…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-18 Alejandro Aviles , Christine Gruber , Orlando Luongo , Hernando Quevedo

This paper introduces a novel cosmological model aimed at probing the accelerated expansion of the late Universe through a unique parametrization of the deceleration parameter. We aim to constrain key cosmic parameters by integrating recent…

General Relativity and Quantum Cosmology · Physics 2024-08-14 Himanshu Chaudhary , Ujjal Debnath , G. Mustafa , S. K. Maurya , Farruh Atamurotov

The theory of universal Taylor series can be extended to the case of Pad\'e approximants where the universal approximation is not realized by polynomials any more, but by rational functions, namely the Pad\'e approximants of some power…

Complex Variables · Mathematics 2015-01-13 N. Daras , G. Fournodavlos , V. Nestoridis

Late time cosmic acceleration may be achieved by modifying gravity on large scales. This should also have consequences on the evolution of perturbations. We thus extend our study of exponential infrared $f(T)$ teleparallel gravity to…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Mahmoud Hashim , Amr A. El-Zant , Waleed El Hanafy , Alexey Golovnev

We apply a new model for the spherically averaged correlation function at large pair separations to the measurement of the clustering of luminous red galaxies (LRGs) made from the SDSS by Cabre and Gaztanaga(2009). Our model takes into…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Ariel G. Sanchez , M. Crocce , A. Cabre , C. M. Baugh , E. Gaztanaga

In this article we obtain new irrationality measures for values of functions which belong to a certain class of hypergeometric functions including shifted logarithmic functions, binomial functions and shifted exponential functions. We…

Number Theory · Mathematics 2023-10-12 Makoto Kawashima , Anthony Poëls

(abridged)Cosmological observational programs often compare their data not only with $\Lambda$CDM, but also with extensions applying dynamical models of dark energy (DDE), with a time-dependent equation of state (EoS) parameter $w$. We…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-13 Horst Foidl , Tanja Rindler-Daller

Cosmography, as an integral branch of cosmology, strives to characterize the Universe without relying on pre-determined cosmological models. This model-independent approach utilizes Taylor series expansions around the current epoch,…

General Physics · Physics 2024-06-11 Seokcheon Lee

Based on the mathematically well defined Pad\'e Theory, a theoretically safe new procedure for the extraction of the pole mass and width of a resonance is proposed. In particular, thanks to the Montessus de Ballore theorem we are able to…

High Energy Physics - Phenomenology · Physics 2015-06-16 P. Masjuan , J. J. Sanz-Cillero

Accurate and efficient methods to evaluate cosmological distances are an important tool in modern precision cosmology. In a flat $\Lambda$CDM cosmology, the luminosity distance can be expressed in terms of elliptic integrals. We derive an…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-12 Maarten Baes , Peter Camps , Dries Van De Putte

According to the separate universe conjecture, spherically symmetric sub-regions in an isotropic universe behave like mini-universes with their own cosmological parameters. This is an excellent approximation in both Newtonian and general…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-14 Gábor Rácz , László Dobos , Róbert Beck , István Szapudi , István Csabai

A cosmological observable measured in a range of redshifts can be used as a probe of a set of cosmological parameters. Given the cosmological observable and the cosmological parameter, there is an optimum range of redshifts where the…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-07 L. Kazantzidis , L. Perivolaropoulos , F. Skara

We examine the Pantheon supernovae distance data compilation in a model independent analysis to test the validity of cosmic history reconstructions beyond the concordance $\Lambda$CDM cosmology. Strong deviations are allowed by the data at…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-19 Benjamin L'Huillier , Arman Shafieloo , Eric V. Linder , Alex G. Kim

Recent observational results suggest that our universe is nearly flat and well modelled within a $\Lambda$CDM framework. The observed values of $\Omega_{m}$ and $\Omega_{\Lambda}$ inevitably involve uncertainties. Motivated by this, we make…

General Relativity and Quantum Cosmology · Physics 2009-11-10 B. Mota , M. J. Reboucas , R. Tavakol

Spatial approximations have been traditionally used in spatial databases to accelerate the processing of complex geometric operations. However, approximations are typically only used in a first filtering step to determine a set of candidate…

Light is affected by local inhomogeneities in its propagation, which may alter distances and so cosmological parameter estimation. In the era of precision cosmology, the presence of inhomogeneities may induce systematic errors if not…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-11 J. A. S. Lima , V. C. Busti , R. C. Santos