Showing papers on "Special relativity (alternative formulations) published in 1980"
TL;DR: In this article, a general scheme for interacting fields, which holds both in special and general relativity, is presented which describes all fields in terms of sets of irreducible spinors, and it is shown that this concept is the appropriate one for an initial value problem on a null cone without constraints.
Abstract: A form of initial value problem is considered in which the initial hypersurface is not spacelike but null. This approach has the striking advantage over the more usual Cauchy problem that all constraints (initial data equations) are eliminated from the theory, for a wide class of interacting fields in special relativity and also for general relativity. The theory is most naturally described in terms of the two-component spinor calculus, for which an elementary introduction is given here. A general scheme for interacting fields, which holds both in special and general relativity, is presented which describes all fields in terms of sets of irreducible spinors. The concept of an exact set of such spinors is introduced and it is shown that this concept is the appropriate one for an initial value problem on a null cone without constraints. The initial data can be expressed in the form of a complex number, called a null datum, defined at each point of the null cone, one corresponding to each spinor. There is the curious feature of these null data that apparently it is sufficient here, to have onehalf as much information per point as in the corresponding Cauchy problem. The classical Maxwell-Dirac theory and the Einstein-Maxwell theory are two examples that can be put into the form of exact sets. The Einstein empty-space equations are also of particular note, and in this case the null datum describes essentially the intrinsic geometry of the null cone. The argument given here as applied to a general exact set is incomplete in two important respects. Firstly it depends on the null data being analytic, and secondly the initial hypersurface must be a cone. However, both these restrictions are removed in the case of certain elementary fields called basic free fields, examples of which are the Weyl neutrino field, the free Maxwell field, and the linearized gravitational field. For these cases a simple explicit formula is introduced which expresses the field at any point in terms of the null datum, as an integral taken over the intersection of the initial null hypersurface with the null cone of the point.
123 citations
01 Jan 1980
28 citations
01 Jan 1980
TL;DR: In this paper, the Reinterpretation Principle is used to avoid information transmissions into the past and to predict the existence of antiparticles within a purely relativistic context, and a third postulate is proposed to avoid the information transmission into the future.
Abstract: In the first part of this paper we consider standard (Special) Relativity and show that a ‘Third Postulate’ (the Reinterpretation Principle) is necessary to avoid information transmissions into the past. Such a Third Postulate allows—at the same time—to predict the existence of antiparticles within a purely relativistic context.
27 citations
24 citations
TL;DR: In this article, the standard four-dimensional theory, together with its physical predictions, is recovered from Cole's theory as a special case, and several different theories of six-dimensional special relativity are compared.
24 citations
24 citations
TL;DR: In this article, the existence of a nonzero rest mass for neutrinos implies the possible existence of galactic size masses of degenerate self-gravitating neutrino.
18 citations
01 Jan 1980
16 citations
TL;DR: In a course entitled as mentioned in this paper, a number of episodes in the history of physics are examined, in order to test the theories of Kuhn, Popper, Lakatos, and others, with regard to any common structure exhibited by the various revolutions that physics has undergone.
Abstract: In a course entitled ’’Revolutions in Physics’’ a number of episodes in the history of physics are examined, in order to test the theories of Kuhn, Popper, Lakatos, and others, with regard to any common structure exhibited by the various revolutions that physics has undergone The conflict between Lorentz’s Electron Theory and Einstein’s Special Relativity becomes a major focal point in the second half of the course for the models of scientific revolutions that are studied
TL;DR: Lorentz ether theory can be formulated in a way that makes it equivalent to relativity under the circumstances of all experiments performed so far except two recent ones which have an accuracy almost sufficient to decide between the theories as mentioned in this paper.
01 Jan 1980
TL;DR: In this paper, the authors argue that the general principle of relativity is neither justified by "fact", nor exemplified by the general theory of relativity, and they argue that such a principle is not justified by fact.
Abstract: Among the principles that are generally taken to underlie the general theory of relativity is a general principle of relativity. Such a principle is supposed to extend the special principle of relativity, which holds observers in uniform motion to be indistinguishable by appeal to the laws of physics, to a requirement on observers in arbitrary states of motion. Starting with physical intuitions described graphically by Galileo, proceeding through a series of formal requirements on reference frames defined on models of space-time theories, and considering other "observations" commonly associated with relativity principles, this paper argues that the general principle of relativity is neither justified by "fact", nor exemplified by the general theory of relativity.
TL;DR: In this paper, a discussion of the principle of causality and its role in the derivation of the Lorentz transformations of special relativity is presented. But the authors do not discuss the role of conformal groups in the description of space-time.
Abstract: This article contains a discussion of the principle of causality and its role in the derivation of the Lorentz transformations of special relativity; in particular, there is an exposition of a key theorem of E. C. Zeeman concerning the relationship between the causal group and the inhomogeneous Lorentz group. In addition there are several remarks on the interchangeability of the geometrical and algebraic modes of expression relating to space-time structure, and an explanation of the role of the conformal group in the description of space-time.
TL;DR: In this paper, the author presents his impression of the principal landmarks in the development of general relativity during the first 30 years after its founding from his vantage point of the present: it is a personal statement.
Abstract: In this paper the author presents his impression of the principal landmarks in the development of general relativity (exclusive of cosmology) during the first 30 years after its founding from his vantage point of the present: it is a personal statement.
TL;DR: In this article, it was argued that Gron's criticism of our treatment of the rotating disk in special relativity is incorrect: our results pertain to an acceleration program different from his but physically no less legitimate.
Abstract: It is argued that Gron's criticism of our treatment of the rotating disk in special relativity is incorrect: Our results pertain to an acceleration program different from his but physically no less legitimate.
TL;DR: In this paper, it was shown that the Fizeau experiment actually cannot discriminate between Galilean and relativistic kinematics, and its status as a test of special relativity was discussed.
Abstract: The motivation and interpretation of the Fizeau experiment are reviewed, and its status as a test of special relativity is discussed. It is shown, with the aid of a simplified, purely mechanical, model of the propagation of light in matter, that the experiment actually cannot discriminate between Galilean and relativistic kinematics.
01 Jan 1980
TL;DR: The Einstein general theory of relativity as discussed by the authors is the most beautiful structure in all of theoretical physics and has been remarkably successful in describing gravitational phenomena, and it has provided a basis for constructing models of the universe.
Abstract: The Einstein general theory of relativity is the most beautiful structure in all of theoretical physics. It has been remarkably successful in describing gravitational phenomena. It has provided a basis for constructing models of the universe. It has also provided a conceptual framework for discussing large-scale phenomena in general.
TL;DR: In this article, the problem of minimal extensions of the Lorentz group by superluminal-like transformations is analyzed, and it is found that the "extended relativity groups" are closely related to the complex Poincare group.
Abstract: The problem of minimal extensions of the Lorentz group by superluminal-like transformations is analysed. It is found that the 'extended relativity groups' are closely related to the complex Poincare group. 'Extended relativity' is then studied as a continuous kinematical symmetry of physical states (not necessarily superluminal), and its quantum-mechanical implications obtained by the construction of some classes of irreducible unitary representations. It is found that, if there are massive or massless states having 'extended relativity' as their kinematical symmetry group, there is a superselection rule operating between these states and ordinary matter. Their mutual interactions may display a new type of spontaneous breaking of PT invariance. The possible relevance of these new hypothetical states to T violation is neutral kaon decays and their observation as real states is discussed in two simple model examples.
TL;DR: In this paper, a solution of the Einstein-Maxwell equations corresponding to source-free electromagnetic field plus pure radiation is obtained, and a particular case of the solution is considered which encompasses many known solutions.
Abstract: A solution of the Einstein-Maxwell equations corresponding to source-free electromagnetic field plus pure radiation is obtained. The solution is algebraically special. A particular case of the solution is considered which encompasses many known solutions. Among them is a radiating Ruban metric.