Showing papers on "Special relativity (alternative formulations) published in 2015"

Editorial for the Special Issue 100 Years of Chronogeometrodynamics: The Status of the Einstein's Theory of Gravitation in Its Centennial Year

Abstract: The present Editorial introduces the Special Issue dedicated by the journal Universe to the General Theory of Relativity, the beautiful theory of gravitation of Einstein, a century after its birth. It reviews some of its key features in a historical perspective, and, in welcoming distinguished researchers from all over the world to contribute it, some of the main topics at the forefront of the current research are outlined.

Probing Strong Field Gravity Through Numerical Simulations

Abstract: This article is an overview of the contributions numerical relativity has made to our understanding of strong field gravity, to be published in the book "General Relativity and Gravitation: A Centennial Perspective", commemorating the 100th anniversary of general relativity.

De Sitter Invariant Special Relativity

Abstract: General Introduction Einstein's Special Relativity De Sitter Invariant Special Relativity dS/AdS Relativistic Quantum Mechanics dS/AdS General Relativity Hydrogen Atom in dS/AdS-Special Relativity Superluminal Neutrino in dS/AdS-Special Relativity Non-relativistic Limit of dS/AdS-Special Relativity

Extended Lorentz Transformations in Clifford Space Relativity Theory

Abstract: Some novel physical consequences of the Extended Relativity Theory in C-spaces (Clifford spaces) were explored recently. In particular, generalized photon dispersion relations allowed for energy-dependent speeds of propagation while still retaining the Lorentz symmetry in ordinary spacetimes, but breaking the extended Lorentz symmetry in C-spaces. In this work we analyze in further detail the extended Lorentz transformations in Clifford Space and their physical implications. Based on the notion of “extended events” one finds a very different physical explanation of the phenomenon of “relativity of locality” than the one described by the Doubly Special Relativity (DSR) framework. A generalized Weyl-Heisenberg algebra, involving polyvector-valued coordinates and momenta operators, furnishes a realization of an extended Poincare algebra in C-spaces. In addition to the Planck constant ħ, one finds that the commutator of the Clifford scalar components of the Weyl-Heisenberg algebra requires the introduction of a dimensionless parameter which is expressed in terms of the ratio of two length scales : the Planck and Hubble scales. We finalize by discussing the concept of “photons”, null intervals, effective temporal variables and the addition/subtraction laws of generalized velocities in C-space.

Teaching the basic concepts of the Special Relativity in the secondary school in the framework of the Theory of Conceptual Fields of Vergnaud

Abstract: Fil: Otero, Maria Rita. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Nucleo de Investigacion en Educacion Ciencia y Tecnologia; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

General relativity and cosmology

Abstract: This year marks the hundredth anniversary of Einstein's 1915 landmark paper "Die Feldgleichungen der Gravitation" in which the field equations of general relativity were correctly formulated for the first time, thus rendering general relativity a complete theory. Over the subsequent hundred years physicists and astronomers have struggled with uncovering the consequences and applications of these equations. This contribution, which was written as an introduction to six chapters dealing with the connection between general relativity and cosmology that will appear in the two-volume book "One Hundred Years of General Relativity: From Genesis and Empirical Foundations to Gravitational Waves, Cosmology and Quantum Gravity," endeavors to provide a historical overview of the connection between general relativity and cosmology, two areas whose development has been closely intertwined.

Three Common Misconceptions in General Relativity

Abstract: We highlight and resolve what we take to be three common misconceptions in general relativity, relating to (a) the interpretation of the weak equivalence principle and the relationship between gravity and inertia; (b) the connection between gravitational redshift results and spacetime curvature; and (c) the strong equivalence principle and the local recovery of special relativity in curved, dynamical spacetime.

Energy-Momentum Tensors and Motion in Special Relativity

Abstract: The notion of “motion” and “conserved quantities”, if applied to extended objects, is already quite non-trivial in Special Relativity. This contribution is meant to remind us on all the relevant mathematical structures and constructions that underlie these concepts, which we will review in some detail. Next to the prerequisites from Special Relativity, like Minkowski space and its automorphism group, this will include the notion of a body in Minkowski space, the momentum map, a characterisation of the habitat of globally conserved quantities associated with Poincare symmetry—so called Poincare charges—the frame-dependent decomposition of global angular momentum into Spin and an orbital part, and, last not least, the likewise frame-dependent notion of centre of mass together with a geometric description of the Moller Radius, of which we also list some typical values. Two Appendices present some mathematical background material on Hodge duality and group actions on manifolds.

Implication of Spatial and Temporal Variations of the Fine-Structure Constant

Abstract: Temporal and spatial variation of fine-structure constant $\alpha\equiv e^2/\hbar c$ in cosmology has been reported in analysis of combination Keck and VLT data. This paper studies this variation based on consideration of basic spacetime symmetry in physics. Both laboratory $\alpha_0$ and distant $\alpha_z$ are deduced from relativistic spectrum equations of atoms (e.g.,hydrogen atom) defined in inertial reference system. When Einstein's $\Lambda eq 0$, the metric of local inertial reference systems in SM of cosmology is Beltrami metric instead of Minkowski, and the basic spacetime symmetry has to be de Sitter (dS) group. The corresponding special relativity (SR) is dS-SR. A model based on dS-SR is suggested. Comparing the predictions on $\alpha$-varying with the data, the parameters are determined. The best-fit dipole mode in $\alpha$'s spatial varying is reproduced by this dS-SR model. $\alpha$-varyings in whole sky is also studied. The results are generally in agreement with the estimations of observations. The main conclusion is that the phenomenon of $\alpha$-varying cosmologically with dipole mode dominating is due to the de Sitter (or anti de Sitter) spacetime symmetry with a Minkowski point in an extended special relativity called de Sitter invariant special relativity (dS-SR) developed by Dirac-In\"{o}n\"{u}-Wigner-G\"{u}rsey-Lee-Lu-Zou-Guo.

Image-based general-relativistic visualization

Abstract: Ego-centric, or first-person, visualization is a valuable tool for an introductory course in general relativity as well as for public outreach to provide a deeper understanding of the geometric distortion effects due to curved spacetime. To enhance this process, interactive visualization allows us to scrutinize the effects in more detail, as the student can change the parameters and see how they influence the visual result without delays. The image-based technique, borrowed from special relativity, is restricted to scenes where all objects can be considered to be infinitely far away, such that one has to deal only with panorama images. While the accompanying Java application can be used already in beginning classes to teach general relativity, the underlying technical details are addressed to the more advanced student who is also interested in implementation details.

Causal Order, Temporal Order, and Becoming in Special Relativity

Abstract: I reconstruct from Rietdijk and Putnam’s well-known papers an argument against the applicability of the concept of becoming in Special Relativity, which I think is unaffected by some of the objections found in the literature. I then consider a line of thought found in the discussion of the possible conventionality of simultaneity in Special Relativity, beginning with Reichenbach, and apply it to the debate over becoming. We see that it immediately renders Rietdijk and Putnam’s argument unsound. I end by comparing my approach to others found in the literature, primarily Stein’s.

Cosmology of modified gravity with a non-local f(R)

Abstract: We consider a modification of GR with a special type of a non-local f(R). The structure of the non-local operators is motivated by the string field theory and p-adic string theory. We pay special account to the stability of the de Sitter solution in our model and formulate the conditions on the model parameters to have a stable configuration. Relevance of unstable configurations for the description of the de Sitter phase during inflation is discussed. Special physically interesting values of parameters are studied in details.

Special relativity from the dynamical viewpoint

Abstract: Arguments are reviewed and extended in favor of presenting special relativity at least in part from a more mechanistic point of view. A number of generic mechanisms are catalogued and illustrated with the goal of making relativistic effects seem more natural by connecting with more elementary aspects of physics, particularly the physics of waves.

Energy-Momentum Tensors and Motion in Special Relativity

Abstract: The notions of "motion" and "conserved quantities", if applied to extended objects, are already quite non-trivial in Special Relativity. This contribution is meant to remind us on all the relevant mathematical structures and constructions that underlie these concepts, which we will review in some detail. Next to the prerequisites from Special Relativity, like Minkowski space and its automorphism group, this will include the notion of a body in Minkowski space, the momentum map, a characterisation of the habitat of globally conserved quantities associated with Poincare symmetry -- so called Poincare charges --, the frame-dependent decomposition of global angular momentum into Spin and an orbital part, and, last not least, the likewise frame-dependent notion of centre of mass together with a geometric description of the Moeller Radius, of which we also list some typical values. Two Appendices present some mathematical background material on Hodge duality and group actions on manifolds. This is a contribution to the book: "Equations of Motion in Relativistic Gravity", edited by Dirk Puetzfeld and Claus Laemmerzahl, to be published by Springer Verlag.

Review of Experiments that Contradict Special Relativity and Support Neo-Lorentz Relativity: Latest Technique to Detect Dynamical Space Using Quantum Detectors

Abstract: The anisotropy of the velocity of EM radiation has been repeatedly detected, including the Michelson-Morley experiment of 1887, using a variety of techniques. The experiments reveal the existence of a dynamical space that has a velocity of some 500km/s from a southerly direction. These consistent experiments contradict the assumptions of Special Relativity, but are consistent with the assumptions of neo-Lorentz Relativity. The existence of the dynamical space has been missed by physics since its beginnings. Novel and checkable phenomena then follow from including this space in Quantum Theory, EM Theory, Cosmology, etc, including the derivation of a more general theory of gravity as a quantum wave refraction effect. The corrected Schrodinger equation has resulted in a very simple and robust quantum detector, which easily measures the speed and direction of the dynamical space. This report reviews the key experimental evidence.

Novel Physical Consequences of the Extended Relativity in Clifford Spaces

Abstract: Novel physical consequences of the Extended Relativity Theory in C-spaces (Clifford spaces) are explored. The latter theory provides a very different physical explanation of the phenomenon of “relativity of locality” than the one described by the Doubly Special Relativity (DSR) framework. Furthermore, an elegant nonlinear momentum-addition law is derived in order to tackle the “soccer-ball” problem in DSR. Neither derivation in C-spaces requires a curved momentum space nor a deformation of the Lorentz algebra. While the constant (energy-independent) speed of photon propagation is always compatible with the generalized photon dispersion relations in C-spaces, another important consequence is that these generalized photon dispersion relations allow also for energy-dependent speeds of propagation while still retaining the Lorentz symmetry in ordinary spacetimes, while breaking the extended Lorentz symmetry in C-spaces. This does not occur in DSR nor in other approaches, like the presence of quantum spacetime foam. We conclude with some comments on the quantization program and the key role that quantum Clifford-Hopf algebras might have in the future developments since the latter q-Clifford algebras naturally contain the κ-deformed Poincare algebras which are essential ingredients in the formulation of DSR.

Special relativity in the school laboratory: a simple apparatus for cosmic-ray muon detection

Abstract: We use apparatus based on two Geiger–Muller tubes, a simple electronic circuit and a Raspberry Pi computer to illustrate relativistic time dilation affecting cosmic-ray muons travelling through the atmosphere to the Earth's surface. The experiment we describe lends itself to both classroom demonstration to accompany the topic of special relativity and to extended investigations for more inquisitive students.

Speakable and Unspeakable in Special Relativity: Time Readings and Clock Rhythms

Abstract: The traditional presentation of special relativity is made from a rupture with previous ideas, such as the notion of absolute motion, emphasizing the antagonism of the Lorentz-Poincare's views and Einstein's ideas. However, a weaker formulation of the postulates allows to recover all the mathematical results from Einstein's special relativity and reveals that both viewpoints are merely different perspectives of one and the same theory. The apparent contradiction simply stems from different procedures for clock "synchronization," associated with different choices of the coordinates used to describe the physical world. Even very fundamental claims, such as the constancy of the speed of light, relativity of simultaneity and relativity of time dilation, are seen to be no more than a consequence of a misleading language adopted in the description of the physical reality, which confuses clock rhythms with clock time readings. Indeed, the latter depend on the "synchronization" adopted, whereas the former do not. As such, these supposedly fundamental claims are not essential aspects of the theory, as reality is not altered by a mere change of coordinates. The relation between the rhythms of clocks in relative motion is derived with generality. This relation, which is not the standard textbook expression, markedly exposes the indeterminacy of special relativity, connected with the lack of knowledge of the value of the one-way speed of light. Moreover, the theory does not collapse and remains valid if some day the one-way speed of light is truly measured and the indeterminacy is removed. It is further shown that the slow transport method of "synchronization" cannot be seen as distinct from Einstein's procedure. c

Information Relativity Theory and its Application to Cosmology

Abstract: In a recent paper [1] I proposed a novel relativity theory termed Information Relativity (IR). Unlike Einstein's relativity which dictates as force majeure that relativity is a true state of nature, Information Relativity assumes that relativity results from difference in information about nature between observers who are in motion relative to each other. The theory is based on two axioms: 1. the laws of physics are the same in all inertial frames of reference (Special relativity's first axiom); 2. All translations of information from one frame of reference to another are carried by light or by another carrier with equal velocity (information-carrier axiom). For the case of constant relative velocities, I showed in the aforementioned paper that IR accounts successfully for the results of a class of relativistic time results, including the Michelson-Morley's "null" result, the Sagnac effect, and the neutrino velocities reported by OPERA and other collaborations. Here I apply the theory, with no alteration, to cosmology. I show that the theory is successful in accounting for several cosmological findings, including the pattern of recession velocity predicted by inflationary theories, the GZK energy suppression phenomenon at redshift z 1.6, and the amounts of matter and dark energy reported in recent ΛCDM cosmologies.

Einstein and Hilbert

Abstract: Highlights of the twenty-odd-year relationship between Einstein and Hilbert are reviewed: the encounter that never took place (1912) when Einstein declined Hilbert’s invitation to Gottingen; the fateful encounter (1915–1916) leading to a dispute over the final formulation of general relativity; the tragic-comic encounter (1928–1929) over editorship of the Annalen der Mathematik leading to what Einstein called “The battle of the Frogs and Mice”; L’envoi (1932) Einstein’s final letter of congratulations to Hilbert on his 70th birthday.

General Derivation of Mass-Energy Relation without Electrodynamics or Einstein’s Postulates

Abstract: The mass-energy equation is derived in general from Newton’s equation of motion without use of electrodynamics, or Einstein’s Postulates which were presented in his superb 1905 paper on Special Relativity (SR). This was previously not thought to be possible. This novel derivation of an accelerated body of rest mass m0 is compared with the traditional SR inertial derivation. A discussion is given of pre-1905, electrostatic and electrodynamic derivations of the mass-energy relation yielding , as well as more recent ones. A concise pre-relativity history of the mass-energy relation is traced back to Newton in 1717.

Holographic special relativity

Abstract: We reinterpret special relativity, or more precisely its de Sitter deformation, in terms of 3d conformal geometry, as opposed to (3+1)d spacetime geometry. An inertial observer, usually described by a geodesic in spacetime, becomes instead a choice of ways to reverse the conformal compactification of a Euclidean vector space up to scale. The observer's "current time," usually given by a point along the geodesic, corresponds to the choice of scale in the decompactification. We also show how arbitrary conformal 3-geometries give rise to "observer space geometries," as defined in recent work, from which spacetime can be reconstructed under certain integrability conditions. We conjecture a relationship between this kind of "holographic relativity" and the "shape dynamics" proposal of Barbour and collaborators, in which conformal space takes the place of spacetime in general relativity. We also briefly survey related pictures of observer space, including the AdS analog and a representation related to twistor theory.

Time in Fundamental Physics

Abstract: The first three sections of this paper contain a broad brush summary of the profound changes in the notion of time in fundamental physics that were brought about by three revolutions: the foundations of mechanics distilled by Newton in his Principia , the discovery of special relativity by Einstein and its reformulation by Minkowski, and, finally, the fusion of geometry and gravity in Einstein׳s general relativity. The fourth section discusses two aspects of yet another deep revision that waits in the wings as we attempt to unify general relativity with quantum physics.

Thomas–Wigner rotation and Thomas precession in covariant ether theories: novel approach to experimental verification of special relativity

Abstract: We continue the analysis of Thomas–Wigner rotation (TWR) and Thomas precession (TP) initiated in (Kholmetskii and Yarman. Can. J. Phys. 92, 1232 (2014). doi:10.1139/cjp-2014-0015; Kholmetskii et al...