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Related papers: On inhomogeneity parameters for Backus average

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We consider a long-wave transversely isotropic (TI) medium equivalent to a series of finely parallel-layered isotropic layers, obtained using the \citet{Backus} average. In such a TI equivalent medium, we verify the \citet{Berrymanetal}…

Geophysics · Physics 2019-01-29 Filip P. Adamus

We propose and constrain with the latest observational data three parameterizations of the deceleration parameter, valid from the matter era to the far future. They are well behaved and do not diverge at any redshift. On the other hand,…

General Relativity and Quantum Cosmology · Physics 2013-01-01 Diego Pavón , Ivan Duran , Sergio del Campo , Ramón Herrera

We theoretically study negative refraction of inhomogeneous waves at the interface of lossy isotropic media. We obtain explicit (up to the sign) expressions for the parameters of a wave transmitted through the interface between two lossy…

Optics · Physics 2014-02-19 Vladimir Yu. Fedorov , Takashi Nakajima

The inhomogeneous six-vertex model is a 2$D$ multiparametric integrable statistical system. In the scaling limit it is expected to cover different classes of critical behaviour which, for the most part, have remained unexplored. For general…

Mathematical Physics · Physics 2021-03-17 Vladimir V. Bazhanov , Gleb A. Kotousov , Sergii M. Koval , Sergei L. Lukyanov

Usually the effects of isotropic inhomogeneities are not seriously taken into account in the determination of the cosmological parameters because of Copernican principle whose statement is that we do not live in the privileged domain in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-02 Hiroyuki Negishi , Ken-ichi Nakao , Chul-Moon Yoo , Ryusuke Nishikawa

The space of $G$-invariant metrics on a homogeneous space $G/H$ is in one-to-one correspondence with the set of inner products on the tangent space $\fr{m}\cong T_{{\it o}}(G/H)$, which are invariant under the isotropy representation. When…

Differential Geometry · Mathematics 2016-03-22 Marina Statha

The breakdown of statistical homogeneity and isotropy of cosmic perturbations is a generic feature of ultra large scale structure of the cosmos, in particular, of non trivial cosmic topology. The statistical isotropy (SI) of the Cosmic…

Astrophysics · Physics 2008-11-26 Tarun Souradeep , Amir Hajian

We consider an inhomogeneous model and independently an anisotropic model of primordial power spectrum in order to describe the observed hemispherical anisotropy in Cosmic Microwave Background Radiation. This anisotropy can be parametrized…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-31 Rahul Kothari , Shamik Ghosh , Pranati K. Rath , Gopal Kashyap , Pankaj Jain

We further study the interfaces arising in a situation of inhomogeneity. More precisely, we identify a characteristic length for the gradient percolation model, that enables us to tighten previous estimates established for it. This allows…

Probability · Mathematics 2009-07-10 Pierre Nolin

The linear stability analysis of a plane Poiseuille flow in a channel with anisotropic and inhomogeneous porous layers is performed. The effect of anisotropy and inhomogeneous permeability on the stability characteristics is addressed in…

Soft Condensed Matter · Physics 2023-05-16 Supriya Karmakar , Priyanka Shukla

The standard model of cosmology is based on the existence of homogeneous surfaces as the background arena for structure formation. Homogeneity underpins both general relativistic and modified gravity models and is central to the way in…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Roy Maartens

Computer simulations show that liquids of molecules with harmonic intramolecular bonds may have "pseudoisomorphic" lines of approximately invariant dynamics in the thermodynamic phase diagram. We demonstrate that these lines can be…

Soft Condensed Matter · Physics 2016-12-30 Andreas Elmerdahl Olsen , Jeppe C. Dyre , Thomas B. Schrøder

The two fundamental assumptions in cosmology are that the Universe is statistically homogeneous and isotropic when averaged on large scales. Given the big implication of these assumptions, there has been a lot of statistical tests carried…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-04 Yabebal Fantaye

We establish a family of parametric isoperimetric-type inequalities with multiple geometric quantities for closed convex curves. These inequalities hold under certain parameter conditions. We also prove the equality conditions. Some new…

Differential Geometry · Mathematics 2026-05-28 Heran Zhao

This paper is devoted to integrability conditions for systems of linear difference and differential equations with difference parameters. It is shown that such a system is difference isomonodromic if and only if it is difference…

Commutative Algebra · Mathematics 2014-04-15 Alexey Ovchinnikov

The most general homogeneous and isotropic statistical ensemble of linear scalar perturbations which are regular at early times, in a universe with only photons, baryons, neutrinos, and a cold dark matter (CDM) component, is described by a…

Astrophysics · Physics 2009-10-31 Martin Bucher , Kavilan Moodley , Neil Turok

A new class of pattern forming systems is identified and investigated: anisotropic systems that are spatially inhomogeneous along the direction perpendicular to the preferred one. By studying the generic amplitude equation of this new class…

Pattern Formation and Solitons · Physics 2015-10-28 B. Kaoui , A. Guckenberger , A. Krekhov , F. Ziebert , W. Zimmermann

We incorporate a version of a spike and slab prior, comprising a pointmass at zero ("spike") and a Normal distribution around zero ("slab") into a dynamic panel data framework to model coefficient heterogeneity. In addition to homogeneity…

Econometrics · Economics 2024-02-07 Hyungsik Roger Moon , Frank Schorfheide , Boyuan Zhang

Recent observational analyses have suggested possible evidence of hemisphere asymmetry in cosmological datasets. Parameterizations of this kind place observers in a privileged position-specifically on the plane that divides the two…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-16 Xin Wang , Zhiqi Huang

In the present paper, the material parameters of the isotropic relaxed micromorphic model derived for a specific metamaterial in a previous contribution are used to model its transmission properties. Specifically, the reflection and…