Showing papers on "Special relativity (alternative formulations) published in 1994"

Quantum non-locality and relativity

Abstract: It is sometimes stated that composite quantum systems in entangled states are fundamentally ‘non-local’(i.e. a measurement on one component system can affect a spacelike separated system ‘instantaneously’) and therefore, non-relativistic quantum mechanics violates Relativity theory. This conclusion is usually thought to follow directly from Bell's Theorem in quantum mechanics and the upper limit on velocities provided by the speed of light in Relativity. But exactly what if the conflict between the kind of non-locality exhibited by entangled quantum systems and either the Special or General Theory of Relativity? Maudlin's Quantum Non-Locality and Relativity is a beautifully crafted book that attempts to answer this question by evaluating four purported restrictions imposed by Relativity. He also considers four attempts to formulate Lorentz invariant quantum theories and concludes that such accounts exact a high philosophical price. Maudlin has achieved his first goal: he gives a lucid exposition of the tension between quantum non-locality and Relativity theory which is accessible to the non-specialist. But is there a high philosophical price to be paid for Lorentz invariant quantum theories and can we afford it?

Spectral shifts in general relativity

Abstract: A unified approach towards spectral shifts in general relativity brings the cosmological and gravitational redshifts within the same framework as the more familiar Doppler effect. This approach was first proposed by Synge [Relativity: The General Theory (North‐Holland, Amsterdam 1960)] and is described here in a more simplified form.

Symplectic Matrices, First Order Systems and Special Relativity

Abstract: The recent developments in canonical transforms, matrix theory, block Kronecker multiplications, and other areas are applied to extend and simplify results in the theory of first order systems and special relativity. Especially noteworthy are the author's results on Fourier transforms in dimensions lower than the surrounding space and his approach to the Doppler effect, which has never been published previously and supersedes previous works on this topic, which failed to solve the Doppler effect exactly. Some of the goals of this work are: to develop the theory of complex symmetric matrices as the rigorous foundations of first order systems, to exhibit in full generality the author's method of duality, and to discuss the neglected area of three dimensional effects in special relativity. The section on special relativity has been especially simplified so that it may be used as a beginning graduate text in this area. It includes the first full discussion of the Lorentz group in a book since Silberstein's pioneering 1913 treatment.

Special Relativity and How it Works

Abstract: 1 Introduction 2 Light and Relativity 3 The Velocities' Play 4 Space-Time 5 Relativity at Work I: Mechanics 6 Relativity at Work II: Electromagnetism and Optics 7 Relativistic Paradoxes 8 Miracles of a Spinning World 9 The Theory of Relativity is the Theory of Absoluteness 10 Relativity at Work III: Quantum Mechanics 11 Relativity and Causality 12 Applied Relativity and Relativistic Engineering 14 A Bit of General Relativity Appendices

Rigid Motion in Special and General Relativity

Abstract: We give a definition of rigid congruences in both General and Special Relativity, and we try to make the definition plausible. To this end we recall Fermat's principle in General Relativity and we show that this principle allows us to reinterpret the “quotient metric” as the quadratic form which defines the optical length in a gravitational field. We apply the definition to the Earth-Sun system in the post-Newtonian approximation. Furthermore we compute the Fermat tensor and the corresponding relative variation of the speed of light in a Michelson-Morley like experiment performed on the Earth's surface. According to all measurements to date, this quantity is extremely small (10 -13 ).

General relativity before special relativity: An unconventional overview of relativity theory

Abstract: It is suggested how Bernhard Riemann might have discovered General Relativity soon after 1854 and how today’s undergraduate students can be given a glimpse of this before, or independently of, their study of Special Relativity At the same time, the whole field of relativity theory is briefly surveyed from the space–time point of view

Teaching special relativity with a computer

Abstract: RelLab, a computer‐based Relativity Laboratory designed to lead high school or introductory college physics students to a qualitative understanding of Special Relativity is described. RelLab is an open‐ended ‘‘construction kit’’ for building a wide variety of gedanken experiments. Students are posed problems by the teacher, usually in the form of paradoxes. They break into small groups to discuss the paradox, construct a gedanken experiment to try to understand and solve it, and then come together as a class to discuss their results. The effectiveness of the software and the pedagogical approach are evaluated by giving high school students a test problem drawn from the physics education literature. The students demonstrated a level of qualitative understanding of relativity superior to that of the graduate students used in a previous study.

Wave front relativity

Abstract: A complete picture of the relativity of wave fronts, heretofore lacking, is presented in the context of an expanding spherical light wave as recorded in two Lorentz frames in relative motion.

GPS, atomic clocks and relativity

Abstract: Discusses position determination of the user, atomic clocks in satellites, special relativity, Lorentz transformation, length contraction, time dilation, Doppler effect, and aging of the Navstar clocks. >

Relativity in a substrate

Abstract: The Reichenbach-Grunbaum thesis of the conventionality of distant simultaneity of special relativity is clarified by developing relativity within a medium. Instead of light, spatially distant clocks are imagined to have been synchronized by 'acoustic signal'. Einstein's procedure for synchrony which assumes that the two-way speed of the synchronizing signal along a given line is the same as its one-way speed, has however been retained. It is shown that by deliberately opting for the non-luminal synchrony (but at the same time following Einstein's procedure for it) and hence by obtaining the transformation equations for the relativistic world one is able to visualize more clearly the conventionality ingredients in the standard formulation of special relativity. The Sjodin point of view of clock synchronization which requires the concept of a preferred inertial frame is seen to be more appropriate in the present context. First, the transformations have been obtained generally and later some special cases have been investigated. The common confusions concerning the 'real' and 'apparent' effects in special relativity have been made clear by studying the transformation equations for the relativistic world and that for the Galilean world under the non-luminal synchrony. It is shown that gamma-factors of special relativity partly originate from Einstein's procedure for clock synchrony.

Special relativity : applications to particle physics and the classical theory of fields

Abstract: Galilean relativity and absolute space basic postulates of special relativity and relativistic kinematics relativistic mechanics relativistic optics relativity and electromagnetism in vacuum relativistic kinematics of binary collisions tachyons.

Six Roads from Newton: Great Discoveries in Physics

Abstract: The Newtonian Universe Waves and Their Differences from Particles Fields: Space Is Not Empty Probability: What Does It Measure? Special Relativity: Only One Velocity Is Absolute Quantum Theory: New Phenomena, New Principles General Relativity: Gravity as Field Distortions A Look Down Further Roads Neither Determinism Nor Indeterminism Road to the Stars Appendices Index.

Relativity on a single sheet

Abstract: Many subjects require students to reassess their existing beliefs and preconceptions. This article uses the example of a first introduction to special relativity to suggest a method for facilitating this often painful process.

Gravitation : the spacetime structure : SILARG VIII : proceedings of the 8th Latin American Symposium on Relativity and Gravitation, Águas de Lindóia, Brazil, 25-30 July 1993

Abstract: Nakedly Singular Solutions of Einstein's Equations (K Lake) Clifford Algebras, Relativity and Quantum Mechanics (P Lounesto) Numerical Relativity and Dynamical Evolution of Black Hole Spacetimes (R Matzner) Soliton and Vacua in Relativity Theory Revisited (G W Gibbons) Cosmic Strings and Their Observational Consequences (E P S Shellard) and 77 research papers by Latin American scientists.

Spatial measures in special relativity do not empirically determine simultaneity relations: A reply to Coleman and Korté

Abstract: Coleman and Korte have restated and defended an earlier attempt to refute the traditional thesis of the conventionality of simultaneity within special relativity. Here we argue their attempt still fails and respond to criticisms of a paper in which we addressed the inadequacies of their earlier paper. The spatial criterion they use to argue for standard synchronization throughout an inertial frame is merely a definition and provides no demonstration that a unique distant simultaneity relation exists in nature.

Bianci-IX cosmological models with rotation in general relativity theory

Abstract: Bianci-IX metrics have been used to obtain new exact solutions to the GRT equations, which may describe the early stages in the evolution of an expanding and rotating universe.

The Physical Meaning of Albert Einstein’s Relativistic Ether Concept

Abstract: In 1905, as is well known A. Einstein began, to deny the existence of an ether as it was concieved in 19th-century physics, in particular of Lorentz’s ether, which was in the first place a privileged reference frame. He denied its existence because it violeted his principle of relativity, according to which there is no privileged reference frame for the formulation of the laws of nature. Nevertheless, in 1916, after the definitive formulation of the general theory of relativity, Einstein prosposed a completely new conception of the ether. In this conception, the new ether does not violate the principle of relativity because the space-time of the theory of relativity is conceived, in it, as a material medium sui generis that can in no way constitute a frame of reference.

Radiating solutions with heat flow in general relativity.

Abstract: In this thesis we model spherically symmetric radiating stars dissipating energy in the form of a radial heat flux. We assume that the spacetime for the interior matter distribution is shear-free. The junction conditions necessary for the matching of the exterior Vaidya solution to an interior radiating line element are obtained. In particular we show that the pressure at the boundary of the star is nonvanishing when the star is radiating (Santos 1985). The junction conditions, with a nonvanishing cosmological constant, were obtained. This generalises the results of Santos (1985) and we believe that this is an original result. The Kramer (1992) model is reviewed in detail and extended. The evolution of this model depends on a function of time which has to satisfy a nonlinear second order differential equation. We solve this differential equation in general and thereby completely describe the temporal behaviour of the Kramer model. Graphical representations of the thermodynamical and gravitational variables are generated with the aid of the software package MATHEMATICA Version 2.0 (Wolfram 1991). We also analyse two other techniques to generate exact solutions to the Einstein field equations for modelling radiating stars. In the first case the particle trajectories are assumed to be geodesics. We indicate how the model of Kolassis et al (1988) may be extended by providing an ansatz to solve a second order differential equation. In the second case we review the models of de Oliveira et al (1985, 1986, 1988) where the gravitational potentials are separable functions of the spatial and temporal coordinates.

In Defense of Newton: A Physicist's View

Abstract: Anthony French joined the faculty of the Massachusetts Insti? tute of Technology in 1962, where he is now Professor Emeritus of Physics. His many books include Principles of Modern Physics, Special Relativity, Newtonian Mechanics, and Introduc? tion to Classical Mechanics. Even before becoming an under? graduate at Cambridge University in 1939 he revered Isaac Newton, and has done so ever since. During the past 20 years, especially, he has had a steadily growing interest in the history of physics, both ancient and modern.

The Theory of Relativity and Science

Abstract: If we are to consider the theory of relativity in a more general context than that of physics including astrophysics, we shall be concerned primarily with its relation to mathematics on the one hand, and to epistemology or the philosophy of nature on the other. It may indeed be said that the relation of physics to these two fields — a relation which has left its characteristic mark on science since the 17th century — has once more been brought into the centre of general interest by the theory of relativity.