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Recent observations on the quasar absorption spectra supply evidence for the variation of the fine structure constant $\alpha$. In this paper, we propose another interpretation of the observational data on the quasar absorption spectra: a…

General Relativity and Quantum Cosmology · Physics 2012-02-15 Zhe Chang , Sai Wang , Xin Li

The aim of this paper is to investigate the differential geometry of immersed surfaces in three-dimensional normed spaces from the viewpoint of affine differential geometry. We endow the surface with a useful Riemannian metric which is…

Differential Geometry · Mathematics 2017-09-06 Vitor Balestro , Horst Martini , Ralph Teixeira

We make precise the heretofore ambiguous statement that anisotropic stress is a sign of a modification of gravity. We show that in cosmological solutions of very general classes of models extending gravity --- all scalar-tensor theories…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-11 Ippocratis D. Saltas , Ignacy Sawicki , Luca Amendola , Martin Kunz

Textures in images can often be well modeled using self-similar processes while they may at the same time display anisotropy. The present contribution thus aims at studying jointly selfsimilarity and anisotropy by focusing on a specific…

Data Analysis, Statistics and Probability · Physics 2015-06-16 S. G. Roux , M. Clausel , B. Vedel , S. Jaffard , P. Abry

A theoretical study is presented of surface waves at a monomolecular surfactant film between an isotropic liquid and a nematic liquid crystal for the case when the surfactant film is in the isotropic two-dimensional fluid phase and induces…

Soft Condensed Matter · Physics 2008-04-15 S. V. Lishchuk

Channel linear Weingarten surfaces in space forms are investigated in a Lie sphere geometric setting, which allows for a uniform treatment of different ambient geometries. We show that any channel linear Weingarten surface in a space form…

Differential Geometry · Mathematics 2024-07-31 Udo Hertrich-Jeromin , Mason Pember , Denis Polly

We present a novel approach to quantifying the morphology of Cosmic Microwave Background (CMB) anisotropy maps. As morphological descriptors, we use shape parameters known as Minkowski functionals. Using the mathematical framework provided…

Astrophysics · Physics 2009-10-30 Jens Schmalzing , Krzysztof M. Gorski

We propose two approaches to cloak the spin waves (magnons) by investigating magnetization dynamics. One approach is based on a spatially inhomogeneous anisotropic magnetic moment tensor. The other mechanism is using a spatially…

Mesoscale and Nanoscale Physics · Physics 2016-04-20 Mehrdad Elyasi , Charanjit S. Bhatia , Cheng-Wei Qiu , Hyunsoo Yang

A method for recognizing the types of linear acoustic gravity waves (AGWs) in the atmosphere from satellite measurements is proposed. It is shown that the polarization relations between fluctuations of wave parameters (velocity, density,…

Atmospheric and Oceanic Physics · Physics 2022-01-05 Yu. O. Klymenko , A. K. Fedorenko , E. I. Kryuchkov , O. K. Cheremnykh , A. D. Voitsekhovska , Yu. O. Selivanov

It is important to develop fast yet accurate numerical methods for seismic wave propagation to characterize complex geological structures and oil and gas reservoirs. However, the computational cost of conventional numerical modeling…

Geophysics · Physics 2015-05-20 Kai Gao , Shubin Fu , Richard L. Gibson , Eric T. Chung , Yalchin Efendiev

We consider the inverse problem of determining the possible presence of an inclusion in a thin plate by boundary measurements. The plate is made by non-homogeneous linearly elastic material belonging to a general class of anisotropy. The…

Analysis of PDEs · Mathematics 2011-09-16 Antonino Morassi , Edi Rosset , Sergio Vessella

The article explores the acoustic equations in inhomogeneous media and the linearized shallow water equations. Two methods for integrating these equations are proposed. The first method is based on the of the Laplace cascade method, while…

Mathematical Physics · Physics 2024-11-19 O. V. Kaptsov

It is shown that unlike the perfect fluid case, anisotropic fluids (principal stresses unequal) may be geodesic, without this implying the vanishing of (spatial) pressure gradients. Then the condition of vanishing four acceleration is…

General Relativity and Quantum Cosmology · Physics 2009-11-07 L. Herrera , J. Martin , J. Ospino

One fundamental motivation to know the dispersive, or frequency dependent characteristics of localized surface plasmons (LSPs) supported by elliptical shaped particles wrapped with graphene sheet, as well as their scattering characteristics…

Optics · Physics 2021-11-24 Mauro Cuevas , Ricardo A. Depine

We consider the variational problem of minimizing an anisotropic perimeter functional under a volume constraint in a Euclidean convex domain. We extend to this setting analytical properties of the isoperimetric profile, topological features…

Differential Geometry · Mathematics 2025-04-14 César Rosales

A connected regular surface in Lorentz-Minkowski 3-space is called a mixed type surface if the spacelike, timelike and lightlike point sets are all non-empty. Lightlike points on mixed type surfaces may be regarded as singular points of the…

Differential Geometry · Mathematics 2019-08-07 Atsufumi Honda

We give criteria for which a principal curvature becomes a bounded $C^\infty$-function at non-degenerate singular points of wave fronts by using geometric invariants. As applications, we study singularities of parallel surfaces and extended…

Differential Geometry · Mathematics 2020-03-25 Keisuke Teramoto

Although travelling faster than the speed of light in vacuum is not physically allowed, the analogous bound in medium can be exceeded by a moving particle. For an electron in dielectric material this leads to emission of photons which is…

Analysis of PDEs · Mathematics 2021-10-18 Antti Kujanpää

The GRAAL experiment could constrain the variations of the speed of light. The anisotropy of the speed of light may imply that the spacetime is anisotropic. Finsler geometry is a reasonable candidate to deal with the spacetime anisotropy.…

High Energy Physics - Phenomenology · Physics 2013-05-23 Zhe Chang , Sai Wang

Possibility of asymmetric square convection is investigated numerically using a few mode Lorenz-like model for thermal convection in Boussinesq fluids confined between two stress free and conducting flat boundaries. For relatively large…

Pattern Formation and Solitons · Physics 2009-10-31 Alaka Das , Ujjal Ghosal , Krishna Kumar