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The identification and modeling of time-varying systems is a fundamental challenge in signal processing and system identification. To address this challenge, we propose a class of time-varying state-space model (SSM) based neural networks…

Machine Learning · Computer Science 2026-05-18 Sanja Karilanova , Subhrakanti Dey , Ayça Özçelikkale

Using a gauge-invariant formalism we derive and solve the perturbed cosmological equations for the BSBM theory of varying fine structure 'constant'. We calculate the time evolution of inhomogeneous perturbations of the fine structure…

General Relativity and Quantum Cosmology · Physics 2009-11-07 John D. Barrow , D. F. Mota

The decomposition of a time series is an essential task that helps to understand its very nature. It facilitates the analysis and forecasting of complex time series expressing various hidden components such as the trend, seasonal…

Methodology · Statistics 2022-04-25 Grzegorz Dudek

We start with a brief account of the latest analysis of the Oklo phenomenon providing the still most stringent constraint on time-variability of the fine- structure constant $\alpha$. Comparing this with the recent result from the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Yasunori Fujii

In this paper, we study in detail a perfect fluid cosmological model with time-varying "constants" using dimensional analysis and the symmetry method. We examine the case of variable "constants" in detail without considering the perfect…

General Relativity and Quantum Cosmology · Physics 2009-12-30 José Antonio Belinchón , Indrajit Chakrabarty

The detection of a spatial variation of the fine-structure constant, alpha, based on study of quasar absorption systems has recently been reported. The physics that causes this alpha-variation should have other observable manifestations,…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-16 J. C. Berengut , V. V. Flambaum , J. A. King , S. J. Curran , J. K. Webb

We show that observational limits on the possible time variation of constants of Nature are significantly affected by allowing for both space and time variation. Bekenstein's generalisation of Maxwell's equations to allow for cosmological…

Astrophysics · Physics 2009-10-31 John D. Barrow , Chris O'Toole

A new method based on large-scale structure observations is proposed to probe a possible time variation of the fine-structure constant ($\alpha$). Our analyses are based on time-delay of Strong Gravitational Lensing and Type Ia Supernovae…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-09 L. R. Colaço , J. E. Gonzalez , R. F. L. Holanda

Calculation of the Dirac hydrogen atom spectrum in the framework of dynamical fine structure constant (alpha) variability discloses a small departure in the laboratory from Sommerfeld's formula for the fine structure shifts, possibly…

Astrophysics · Physics 2007-05-23 Jacob D. Bekenstein

I review recent constraints on and claimed detections of a time-varying fine-structure constant $\alpha$. Our results are consistent with no variation in $\alpha$ from the epoch of recombination to the present day, and restrict any such…

High Energy Physics - Phenomenology · Physics 2016-09-06 C. J. A. P. Martins

In this paper the problems of the retrospective analysis of models with time-varying structure are considered. These models include contamination models with randomly switching parameters and multivariate classification models with an…

Statistics Theory · Mathematics 2017-10-31 Boris Brodsky , Boris Darkhovsky

We investigate the variation of the fine-structure constant, {\alpha}, in symmetron models using N-body simulations in which the full spatial distribution of {\alpha} at different redshifts has been calculated. In particular, we obtain…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-29 Marvin F. Silva , Hans A. Winther , David F. Mota , C. J. A. P. Martins

We describe a rigorous construction, using matched asymptotic expansions, which establishes under very general conditions that local terrestrial and solar-system experiments will measure the effects of varying `constants' of Nature…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Douglas J. Shaw , John D. Barrow

The time variation of fundamental mass scales can have profound cosmological implications. We investigate a particular model of crossover quintessence which is compatible with all present cosmological observations. This model can also…

High Energy Physics - Phenomenology · Physics 2017-08-23 C. Wetterich

There has been some evidence that the fine structure "constant" $\alpha$ may vary with time. We point out that this variation can be described by a scalar field in some supergravity theory in our toy model, for instance, the N=8 extended…

High Energy Physics - Phenomenology · Physics 2009-11-10 Qing-Guo Huang , Miao Li

We formulate the time variation of the gravitational coupling constant in all dimensions. We show that the time variation of the gravitational coupling constant is related to the time variation of the Newton's constant in three-space…

High Energy Physics - Theory · Physics 2007-10-16 Forough Nasseri

Time variation of Newtonian gravitational constant, $G$, is studied in the model universe with variable space dimension proposed recently. Using the Lagrangian formulation of these models, we find the effective gravitational constant as a…

General Relativity and Quantum Cosmology · Physics 2011-08-17 R. Mansouri , F. Nasseri , M. Khorrami

Many models of quintessence predict a time variation of the fundamental constants as well as a composition-dependent gravity like long-range force mediated by the cosmon. We present bounds for the cosmon coupling to matter and radiation…

High Energy Physics - Phenomenology · Physics 2009-11-07 C. Wetterich

Searches for variations of fundamental constants require accurate measurement errors. There are several potential sources of errors and quantifying each one accurately is essential. This paper addresses one source of uncertainty relating to…

Instrumentation and Methods for Astrophysics · Physics 2022-12-02 Chung-Chi Lee , John K. Webb , Darren Dougan , Vladimir A. Dzuba , Victor V. Flambaum

Our goal is to interpret the energy equation from Doubly Special Relativity (DSR) of Magueijo-Smolin with an invariant Planck energy scale in order to obtain the speed of light with an explicit dependence on the background temperature of…

General Physics · Physics 2017-11-23 Claudio Nassif , A. C. Amaro de Faria
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