Showing papers on "Special relativity (alternative formulations) published in 1970"
TL;DR: In this paper, the conservation laws based upon the existence of curvature and Ricci collineations are investigated and the results given recently by Katzin, Levine and Davis are reinterpreted and generalized.
Abstract: The conservation laws based upon the existence of curvature and Ricci collineations are investigated and the results given recently by Katzin, Levine and Davis are reinterpreted and generalized. The concept of a ‘Maxwell collineation’ is introduced and corresponding conservation laws are found.
29 citations
TL;DR: Elasticity theory in general relativity formulated from classical nonlinear three dimensional theory, discussing thermodynamics and weak field limit was discussed in this paper, where the authors discussed thermodynamics, weak fields, and weak fields.
Abstract: Elasticity theory in general relativity formulated from classical nonlinear three dimensional theory, discussing thermodynamics and weak field limit
24 citations
16 citations
13 citations
TL;DR: In this paper, simple theorems and relations for charged- dust distributions in general relativity were presented, and some simple relations for the distribution of charged-dust distributions were established.
Abstract: The paper presents some simple theorems and relations for charged- dust distributions in general relativity.
13 citations
01 Jan 1970
TL;DR: The existence of Tachyons has been suspected and sought for a long time as mentioned in this paper on the ground that they appear to be compatible with the laws of nature, particularly with Special Relativity, and so there is at least some likelihood that they exist.
Abstract: ‘Tachyons’ are hypothetical faster-than-light particles1 Their existence has been suspected and sought,2 on the ground that they appear to be compatible with the laws of nature, particularly with Special Relativity, and so there is at least some likelihood that they exist That last mad inferential leap is justified by the experience of particle physicists, summed up in ‘Gell-Mann’s totalitarian principle’ that “whatever is not forbidden is compulsory” Experimental searches made so far have failed to find them
11 citations
TL;DR: The principles of relativity are assertions about the structure of physical laws, whose validity or nonvalidity can only be empirically confirmed or falsified as mentioned in this paper, and the weakest forms of those principles are the so-called global propositions, which furnish statements as to which operations, assumed to be performed simultaneously throughout the whole universe, have no influence upon the physical events.
Abstract: The principles of relativity are assertions about the structure of physical laws, whose validity or nonvalidity can only be empirically confirmed or falsified. The weakest forms of those principles are the so-calledglobal propositions. They furnish statements as to which operations—assumed to be performed simultaneously throughout the whole universe—have no influence upon the physical events. Much stronger principles are those of alocal nature. These assert that the physical properties of a system do not change, when the relation of the system is altered vis-a-vis the universe at large. On formulating these local principles, we presuppose either that it is possible to eliminate any influence of the environment or that the influence can be compensated as in the case of universal forces (e.g., gravitational) which can principally not be removed. Still weaker, however, are those formulations of the relativity principles which postulate relativity only for infinitesimally small space-time domains or regions. This distinction yields clarification of all discussions about existence and meaning of a general relativity principle. Such an analysis was already performed by Einstein and Abraham in 1912.
TL;DR: In this paper, it was shown that the Lagrangian of general relativity can be chosen so thatS = ∫pmngmnd3x without the requirement of special boundary conditions.
Abstract: In follow-up of an earlier paper by Komar it is shown that the Lagrangian of general relativity can be chosen so thatS=∫pmngmnd3x. This result holds without the requirement of special boundary conditions.
TL;DR: Carmeli, Carmeli, Fickler, and Witten as discussed by the authors presented a paper on the Relativity Conference in the Midwest, Cincinnati, Ohio, June 2-6, 1969.
Abstract: Relativity Edited by Moshe Carmeli, Stuart I. Fickler and Louis Witten. (Proceedings of the Relativity Conference in the Midwest, Cincinnati, Ohio, June 2–6, 1969.) Pp. xii + 381. (Plenum: New York and London, 1970.) $20; 180s.
01 Jan 1970
TL;DR: In this article, a class of solutions of the Einstein-Maxwell equations corresponding to stationary null electromagnetic fields in otherwise empty space is presented, where the electromagnetic field is defined as a stationary null field.
Abstract: The author presents a class of solutions of Einstein-Maxwell equations corresponding to stationary null electromagnetic fields in otherwise empty space.
TL;DR: In this paper, a generalized Carnot cycle is defined for thermodynamic systems with stationary gravitational fields, where the two heat reservoirs are assumed to be located at different points in space and the Carnot engine is allowed to change its position during the cycle.
Abstract: A generalization of ordinary Carnot cycles is given for thermodynamic systems with stationary gravitational fields. The two heat reservoirs are assumed to be located at different points in space. In addition to the standard change of thermodynamic quantities the Carnot ~ngine is allowed to change its position during the cycle. A ·generalized Carnot cycle' is then defined by the following process: ( 1) Connection of the Carnot engine with the first heat reservoir (exchanging heat), (2) Change of position of the Carnot engine from the first to the second heat reservoir, (3) Connection of the Carnot engine with the second heat reservoir (exchanging heat), (4) Change of position of the Carnot engine from the second to the first heat reservoir, after which the cycle repeats. In all changes of position the presence of the gravitational field has to be considered. The special case of an ordinary Carnot cycle is obtained when there is no gravitational field or when the heat reservoirs are located at the same point. Under the assumption that gravitation can be described by general relativity the efficiency of these generalized Carnot cycles is calculated for stationary fields. Thermodynamic equilibrium exists when the efficiency of a generalized Carnot cycle operating between any two parts of the system is zero. Forthis case we find that T • II ~ II is a constant independent of position. As used here T is the ordinary thermodynamic temperature and II ~ II denotes the norm field of the Killing vector field ~, representing the stationarity of the gravitational field. The proof is independent of the field equations of general relativity. Consequently equilibrium consists of a temperature field which depends on the gravitational field. For static fields with spherical symmetry Tolman has proved this relation by using the field equation of general relativity. Our results show that this relation holds quite generally for arbitrary stationary fields.
01 Aug 1970
TL;DR: In this article, the authors discuss work in three areas of research connected with general relativity: the development of trapped surfaces, a new approach to equations of motion, and some applications of group theory to general relativity, in particular to equation of motion.
Abstract: : The report discusses work in three areas of research connected with general relativity: The development of trapped surfaces; A new approach to equations of motion; and Some applications of group theory to general relativity, in particular to equations of motion. (Author)
Journal Article•