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Related papers: Updated constraints on spatial variations of the f…

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Large-scale structure surveys can be used to measure the dipole in the cosmic microwave background (CMB), in the luminosity distances inferred from type-Ia supernova observations, and in the spatial distribution of galaxies and quasars. The…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-08 Jaiyul Yoo , Matteo Magi , Dragan Huterer

In order to best improve constraints on cosmological parameters and on models of modified gravity using current and future galaxy surveys it is necessary maximally exploit the available data. As redshift-space distortions mean statistical…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-27 Donough Regan

We obtain constraints on the variation of the fundamental constants from the full shape of the redshift-space correlation function of a sample of luminous galaxies drawn from the Data Release 9 of the Baryonic Oscillations Spectroscopic…

The Single Ion Differential alpha Measurement (SIDAM) method for measuring fine stucture variations (daa)and its figures of merit are illustrated together with the results produced by means of FeII absorption lines of QSO intervening…

Astrophysics · Physics 2009-06-23 Paolo Molaro , Dieter Reimers , Irina I. Agafonova , Sergei A. Levshakov

The cosmological principle asserting the large-scale uniformity of the Universe is a testable assumption of the standard cosmological model. We explore the constraints on anisotropic expansion provided by measuring directional variation in…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-07 Paula Boubel , Matthew Colless , Khaled Said , Lister Staveley-Smith

We test the prediction of the time variation of the fine structure constant in the string dilaton model proposed by Damour and Polyakov. First, we analize the dependence of all available observational and experimental data with the fine…

Astrophysics · Physics 2007-05-23 Susana J. Landau , Melina Bersten , Pablo Sisterna , Hector Vucetich

We consider random perturbations of discrete-time dynamical systems. We give sufficient conditions for the stochastic stability of certain classes of maps, in a strong sense. This improves the main result in J. F. Alves, V. Araujo, Random…

Dynamical Systems · Mathematics 2010-03-01 Jose F. Alves , Helder Vilarinho

Over a period of eight months, we have monitored transition frequencies between nearly degenerate, opposite-parity levels in two isotopes of atomic dysprosium (Dy). These transition frequencies are highly sensitive to temporal variation of…

Atomic Physics · Physics 2008-11-26 A. Cingoz , A. Lapierre , A. -T. Nguyen , N. Leefer , D. Budker , S. K. Lamoreaux , J. R. Torgerson

We discuss the effects of finite sky coverage and the uncertainty in extracting information about the power spectrum from experiments on small angular scales. In general the cosmic variance is enhanced by a factor of $4\pi/A$, where $A$ is…

Astrophysics · Physics 2009-10-22 Douglas Scott , Mark Srednicki , Martin White

The important studies of Peebles, and Bond and Efstathiou have led to the formula C_l = const/[l(l +1)] aimed at describing the lower order multipoles of the CMBR temperature variations caused by density perturbations with the flat…

General Relativity and Quantum Cosmology · Physics 2009-10-31 A. Dimitropoulos , L. P. Grishchuk

We prove that the statistical properties of random perturbations of a nonuniformly hyperbolic diffeomorphism are described by a finite number of stationary measures. We also give necessary and sufficient conditions for the stochastic…

Dynamical Systems · Mathematics 2011-11-10 Jose F. Alves , Vitor Araujo , Carlos H. Vasquez

We study the evolution of the fine-structure constant, $\alpha$, induced by non-linear density perturbations in the context of the simplest class of quintessence models with a non-minimal coupling to the electromagnetic field, in which the…

Astrophysics · Physics 2009-11-13 P. P. Avelino , C. J. A. P. Martins , J. Menezes , C. Santos

There is a growing interest in astrophysical tests of the stability of dimensionless fundamental couplings, such as the fine-structure constant $\alpha$, as an optimal probe of new physics. The imminent arrival of the ESPRESSO spectrograph…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-25 C. S. Alves , A. C. O. Leite , C. J. A. P. Martins , T. A. Silva , S. A. Berge , B. S. A. Silva

Astrophysical tests of the stability of Nature's fundamental couplings are a key probe of the standard paradigms in fundamental physics and cosmology. In this report we discuss updated constraints on the stability of the fine-structure…

High Energy Physics - Phenomenology · Physics 2015-08-26 S. M. João , C. J. A. P. Martins , I. S. A. B. Mota , P. M. T. Vianez

Using modifications of Lindeberg's interpolation technique, I propose a new identification-robust test for the structural parameter in a heteroskedastic instrumental variables model. While my analysis allows the number of instruments to be…

Econometrics · Economics 2024-12-17 Manu Navjeevan

We present new constraints on possible features in the primordial inflationary density perturbations power spectrum in light of the recent Cosmic Microwave Background Anisotropies measurements from the Planck satellite. We found that the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Micol Benetti

(Abridged)Motivated by the recent results of Hansen et al. (2008) concerning a noticeable hemispherical power asymmetry in the WMAP data on small angular scales, we revisit the dipole modulated signal model introduced by Gordon et al.…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 J. Hoftuft , H. K. Eriksen , A. J. Banday , K. M. Gorski , F. K. Hansen , P. B. Lilje

In 1976, Shlyakhter showed that the Sm data from Oklo results in the upper bound on the time-variability of the fine-structure constant: $|\dot{\alpha}/\alpha| \lsim 10^{-17}{\rm y}^{-1}$, which has ever been the most stringent bound. Since…

Astrophysics · Physics 2009-11-07 Yasunori Fujii

The Delta-variance analysis is an efficient tool for measuring the structural scaling behaviour of interstellar turbulence in astronomical maps. In paper I we proposed essential improvements to the Delta-variance analysis. In this paper we…

Astrophysics · Physics 2009-11-13 V. Ossenkopf , M. Krips , J. Stutzki

Cosmological variations in the fine structure constant, alpha, can be probed through precise velocity measurements of metallic absorption lines from intervening gas clouds seen in spectra of distant quasars. Data from the Keck/HIRES…

Astrophysics · Physics 2019-08-13 Paolo Molaro , Michael T. Murphy , Sergei Levshakov
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