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Hyperbolic metamaterials may be used to model a 2+1 dimensional Minkowski spacetime in which the role of time is played by one of the spatial coordinates. When a metamaterial is built and illuminated with a coherent extraordinary laser…

Optics · Physics 2015-06-11 Igor I. Smolyaninov

In this work we establish a version of the Bartnik Splitting Conjecture in the context of Lorentzian length spaces. In precise terms, we show that under an appropriate timelike completeness condition, a globally hyperbolic Lorentzian length…

Differential Geometry · Mathematics 2024-12-13 José Luis Flores , Jónatan Herrera , Didier A. Solis

Within the low-energy effective field theories of QED and gravity, the low-energy speed of light or that of gravitational waves can typically be mildly superluminal in curved spacetimes. Related to this, small scattering time advances…

High Energy Physics - Theory · Physics 2020-10-28 Claudia de Rham , Andrew J. Tolley

Recent links between Finsler Geometry and the geometry of spacetimes are briefly revisited, and prospective ideas and results are explained. Special attention is paid to geometric problems with a direct motivation in Relativity and other…

Differential Geometry · Mathematics 2015-06-17 Miguel A. Javaloyes , Miguel Sánchez

We consider spacetime to be a 4-dimensional differentiable manifold that can be split locally into time and space. No metric, no linear connection are assumed. Matter is described by classical fields/fluids. We distinguish electrically…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Friedrich W. Hehl , Yuri N. Obukhov

Reasonable spacetimes are non-compact and of dimension larger than two. We show that these spacetimes are globally hyperbolic if and only if the causal diamonds are compact. That is, there is no need to impose the causality condition, as it…

General Relativity and Quantum Cosmology · Physics 2019-09-17 R. A. Hounnonkpe , E. Minguzzi

Some well-known Lorentzian concepts are transferred into the more general setting of cone structures, which provide both the causality of the spacetime and the notion of cone geodesics without making use of any metric. Lightlike…

Differential Geometry · Mathematics 2023-09-20 Miguel Ángel Javaloyes , Enrique Pendás-Recondo

In this paper, it is shown why Lorentz Transformation implies the general case where observed events are not necessarily in the inertia frame of any observer but assumes a special scenario when determining the length contraction and time…

General Physics · Physics 2012-09-24 Ibrahim M. Alabdulmohsin

We discuss the most general form of the Lorentz transformation in 1+1 dimensional spacetime, focusing mainly on its superluminal branch. For this purpose, we introduce the 2-velocity of a reference frame and the clockwork postulate. Basic…

General Physics · Physics 2025-10-17 Bogdan S. Damski

In this letter we discuss the possibility of treating the spacetime by itself as a kind of deformable body for which we can define an fundamental lattice, just like atoms in crystal lattices. We show three signs pointing in that direction.…

General Relativity and Quantum Cosmology · Physics 2007-05-30 M. O. Tahim , R. R. Landim , C. A. S. Almeida

In this paper I argue for a reassessment of special relativity. The fundamental theory of relativity applicable in this Universe has to be consistent with the existence of the massive Universe, and with the effects of its gravitational…

General Relativity and Quantum Cosmology · Physics 2007-05-23 C. S. Unnikrishnan

The subject of limit curve theorems in Lorentzian geometry is reviewed. A general limit curve theorem is formulated which includes the case of converging curves with endpoints and the case in which the limit points assigned since the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 E. Minguzzi

Relative motion in space with multifractal time (fractional dimension of time close to integer $d_{t}=1+\epsilon (r,t), \epsilon \ll 1$) for "almost" inertial frames of reference (time is almost homogeneous and almost isotropic) is…

General Relativity and Quantum Cosmology · Physics 2007-05-23 L. Ya. Kobelev

The modified Lorentz transformation of a distance-dependent special theory of relativity - which will be briefly summarized - predicts the possibility of superluminal velocity of very distantly moving material bodies to be connected with…

General Physics · Physics 2007-05-23 Ernst Karl Kunst

The notion of maximal extension of a globally hyperbolic space-time arises from the notion of maximal solutions of the Cauchy problem associated to the Einstein's equations of general relativity. In 1969 Choquet-Bruhat and Geroch proved…

Differential Geometry · Mathematics 2014-01-08 Clara Rossi Salvemini

Sub-wavelength confinement of light in nonlinear hyperbolic metamaterials due to formation of spatial solitons has attracted much recent attention because of its seemingly counter-intuitive behavior. In order to achieve self-focusing in a…

Optics · Physics 2015-06-16 Igor I. Smolyaninov

Even a fundamental symmetry like Lorentz Invariance is an experimental fact and must be experimentally verified. We show that the study of the interactions of Cosmic Rays with universal diffuse background radiation can provide very…

Astrophysics · Physics 2007-05-23 Aurelio F. Grillo , Roberto Aloisio

In this paper, we use our results concerning temporal foliations of causal sets in order to provide a new proof of Geroch's Theorem on temporal foliations in a globally hyperbolic spacetime.

General Relativity and Quantum Cosmology · Physics 2021-03-25 Ali Bleybel

A new approach in the Newtonian space and time, based upon the assumption that inertial mass is the quantitative measure of the matter. It has been shown that in case of a special physical system, a supposed matter transfer may reproduce…

General Physics · Physics 2013-08-13 P. Doleschall

It is demonstrated that any two reference frames (RFs), which are uniformly and rectilinearly moving relative to each other, can be adjusted via (possibly anisotropic) rescaling and re-synchronization so that the resulting pair of RFs is…

Classical Physics · Physics 2007-05-23 Iosif Pinelis