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Related papers: One-loop kernels in scale-dependent Horndeski theo…

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We study the phenomenology of the beyond Horndeski class of scalar-tensor theories of gravity, which on cosmological scales can be characterised in terms of one extra function of time, $\alpha_{\rm H}$, as well as the usual four Horndeski…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-04 Dina Traykova , Emilio Bellini , Pedro G. Ferreira

In the present work, we study four-dimensional black strings in Horndeski models with translation invariance. Imposing that the scalar field depends on the string-generator coordinate, the Klein-Gordon equation admits a linear profile as a…

High Energy Physics - Theory · Physics 2023-11-30 Luis Guajardo

In this note we collect, systemise and generalise the existing results for relations between general Horndeski theories and beyond Horndeski theories via disformal transformations of metric. We derive additional disformal transformation…

High Energy Physics - Theory · Physics 2022-06-29 S. Mironov , V. Volkova

We apply the Lagrangian perturbation theory with time-dependent growth functions at second and third order of perturbation with the aim to model the effect of dynamical dark energy on redshift-space distortions. Our fiducial galaxy redshift…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-14 Chakkrit Kaeonikhom , Teeraparb Chantavat

This article gives a concise overview of the development and current status of studies on healthy models of the early Universe without an initial singularity, namely the cosmological bounce and Genesis scenarios, constructed within a broad…

General Relativity and Quantum Cosmology · Physics 2025-01-20 S. Mironov , V. Volkova

We consider Horndeski cosmological models able to screen the vacuum energy coming from any field theory assuming that after this screening the space should be in a de Sitter vacuum with a particular value of the cosmological constant…

General Relativity and Quantum Cosmology · Physics 2015-04-15 Prado Martin-Moruno , Nelson J. Nunes , Francisco S. N. Lobo

We define fully non-perturbative generalizations of the uniform density and comoving curvature perturbations, which are known, in the linear theory, to be conserved on sufficiently large scales for adiabatic perturbations. Our non-linear…

Astrophysics · Physics 2009-11-10 David Langlois , Filippo Vernizzi

Many scientific problems involve data exhibiting both temporal and cross-sectional dependencies. While linear dependencies have been extensively studied, the theoretical analysis of regression estimators under nonlinear dependencies remains…

Statistics Theory · Mathematics 2025-02-27 Marie-Christine Düker , Adam Waterbury

Scalar fields have played an important role in the development of the fundamental theories of physics as well as in other branches of physics such as gravitation and cosmology. For a long time these escaped detection until 2012 year when…

General Relativity and Quantum Cosmology · Physics 2019-05-29 Israel Quiros

We analyze time-dependent dark energy equations of state through linear and nonlinear structure formation and their quintessence potentials, characterized by fast, recent transitions, inspired by parameter space studies of selected classes…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-12 Orlando Luongo , Francesco Pace , Sebastiano Tomasi

We present a detailed study of a simple scalar field model that yields non-singular cosmological solutions. We study both the qualitative dynamics of the homogeneous and isotropic background and the evolution of inhomogeneous linear…

Astrophysics · Physics 2009-11-10 Laura E. Allen , David Wands

We derive a minimal basis of kernels furnishing the perturbative expansion of the density contrast and velocity divergence in powers of the initial density field that is applicable to cosmological models with arbitrary expansion history,…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-14 Michael Hartmeier , Mathias Garny

We propose and construct a two-parameter perturbative expansion around a Friedmann-Lema\^{i}tre-Robertson-Walker geometry that can be used to model high-order gravitational effects in the presence of non-linear structure. This framework…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-15 Sophia R. Goldberg , Timothy Clifton , Karim A. Malik

We study the evolution of Bianchi-I space-times within the framework of the Horndeski theory with $G_5=\text{const}/X$. The space-times are filled a global unidirectional electromagnetic field interacting with a scalar field. We consider…

General Relativity and Quantum Cosmology · Physics 2024-07-26 Ruslan K. Muharlyamov , Tatiana N. Pankratyeva , Shehabaldeen O. A. Bashir

We construct a concrete model of Horndeski bounce with strong gravity in the past. Within this model we show that the correct spectra of cosmological perturbations may be generated at early contracting epoch, with mild fine-tuning ensuring…

High Energy Physics - Theory · Physics 2024-10-04 Y. Ageeva , P. Petrov , V. Rubakov

We consider the problem of high-dimensional non-linear variable selection for supervised learning. Our approach is based on performing linear selection among exponentially many appropriately defined positive definite kernels that…

Machine Learning · Computer Science 2009-09-08 Francis Bach

Redshift-space clustering distortions provide one of the most powerful probes to test the gravity theory on the largest cosmological scales. We perform a systematic validation study of the state-of-the-art statistical methods currently used…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-27 Jorge Enrique García-Farieta , Federico Marulli , Lauro Moscardini , Alfonso Veropalumbo , Rigoberto A. Casas-Miranda

Perturbation theory is a powerful tool for studying large-scale structure formation in the universe and calculating observables such as the power spectrum or bispectrum. However, beyond linear order, typically this is done by assuming a…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-09 Nicholas Choustikov , Zvonimir Vlah , Anthony Challinor

This article is intended to review the recent developments in the Horndeski theory and its generalization, which provide us with a systematic understanding of scalar-tensor theories of gravity as well as a powerful tool to explore…

General Relativity and Quantum Cosmology · Physics 2019-07-22 Tsutomu Kobayashi

In the Horndeski's most general scalar-tensor theories, we derive the three-point correlation function of scalar non-Gaussianities generated during single-field inflation in the presence of slow-variation corrections to the leading-order…

High Energy Physics - Theory · Physics 2015-06-12 Antonio De Felice , Shinji Tsujikawa