Showing papers on "Special relativity (alternative formulations) published in 1989"
Journal Article•
TL;DR: In this article, the Schroedinger dynamics and the projection postulate are unified and a non deterministic generalization of the Schröter equation compatible with relativity is presented. And a symmetry preserving generalisation of the Ghirardi-Rimini-Weber model is presented for quantum dynamical semigroups, including the damped harmonic oscillator and spin relaxation.
Abstract: Our aim is to unify the Schroedinger dynamics and the projection postulate. We first prove that the Schroedinger evolution is the only quantum evolution that is deterministic and compatible with relativity. Next we present a non deterministic generalization of the Schroedinger equation compatible with relativity. This time continuous pure state valued stochastic process covers the whole class of quantum dynamical semigroups, as exemplified by the damped harmonic oscillator and spin relaxation. Finally a symmetry preserving generalization of the Ghirardi-Rimini-Weber model is presented. (orig.).
513 citations
TL;DR: In this article, a unified view of the boost-rotation-symmetric space-times from a unified point of view is presented, where the authors show how one can construct any asymptotically flat Boost-Rotation-Symmetric solution of the flat-space wave equation.
Abstract: This paper deals for the first time with boost-rotation-symmetric space-times from a unified point of view. Boost-rotation-symmetric space-times are the only explicitly known exact solutions of the Einstein vacuum field equations which describe moving singularities or black holes, are radiative and asymptotically flat in the sense that they admit global, though not complete, smooth null infinity, as well as spacelike and timelike infinities. They very likely represent the exterior fields of uniformly accelerated sources in general relativity and may serve as tests of various approximation methods, as nontrivial illustrations of the theory of the asymptotic structure of radiative space-times, and as test beds in numerical relativity. Examples are the {ital C}-metric or the solutions of Bonnor and Swaminarayan. The space-times are defined in a geometrical manner and their global properties are studied in detail, in particular their asymptotic structure. It is demonstrated how one can construct any asymptotically flat boost-rotation-symmetric space-time starting from the boost-rotation-symmetric solution of the flat-space wave equation. The problem of uniformly accelerated sources in special relativity is also discussed. The radiative properties and specific examples of the boost-rotation-symmetric space-times will be analyzed in a following paper.
123 citations
TL;DR: In this paper, a variation on the twin paradox of special relativity is presented where twins undergo the same acceleration for the same length of time, yet they age differently, and it is shown that the acceleration experienced by a relativistic traveler is directly related to the rate at which that traveler ages.
Abstract: A variation on the ‘‘twin paradox’’ of special relativity is presented wherein twins undergo the same acceleration for the same length of time, yet they age differently. Although this problem is simple to solve, it gets to the heart of the behavior of clocks in special relativity and, hopefully, will help to dispel the notion students develop that the acceleration experienced by a relativistic traveler is directly related to the rate at which that traveler ages.
40 citations
01 Jun 1989
TL;DR: In this article, the authors give a definitive treatment to the clocks problem showing that Sachs' "convincing mathematical arguments" are non sequitur and that his later view of the twin paradox coincides with the one derived from the rigorous theory of time developed in this paper.
Abstract: The purpose of the present paper is to reply to a misleading paper by M. Sachs entitled “Einstein's later view of the Twin Paradox” (TP) (Found. Phys.15, 977 (1985)). There, by selecting some passages from Einstein's papers, he tried to convince the reader that Einstein changed his mind regarding the asymmetric aging of the twins on different motions. Also Sachs insinuates that he presented several years ago “convincing mathematical arguments” proving that the theory of relativity does not predict asymmetrical aging in the TP. Here we give a definitive treatment to the clocks problem showing that Sachs' “convincing mathematical arguments” are non sequitur. Also, by properly quoting Einstein, we show that his later view of the TP coincides with the one derived from the rigorous theory of time developed in this paper.
35 citations
TL;DR: The variational theory of an ideal fluid with spin is formulated in Riemannian spacetime within the framework of general relativity theory in this article, and applied in cosmology, showing the very weak influence of spin on gravity.
Abstract: The variational theory of an ideal fluid with spin is formulated in Riemannian spacetime within the framework of general relativity theory. It is applied in cosmology, showing the very weak influence of spin on gravity.
28 citations
TL;DR: The Lorentz group, which is the language of special relativity, is a useful theoretical toll in modern optics, which can serve as analog computers for special relativity.
Abstract: The Lorentz group, which is the language of special relativity, is a useful theoretical toll in modern optics. Optics experiments can therefore serve as analog computers for special relativity. Possible optics experiments involving squeezed states are discussed in connection with the Thomas precession and the Wigner rotation.
28 citations
TL;DR: In this paper, interactive graphics displays have been developed for personal computers that help students visualize this world in the form of interactive graphics utilities that students use to carry out homework exercises and take-home projects.
Abstract: No one can experience directly the world of the very fast, described by special relativity. Interactive graphics displays have been developed for personal computers that help students visualize this world. They are in the form of interactive graphics utilities that students use to carry out homework exercises and take‐home projects. Sequential versions of these programs have been used for 3 years in classes in various institutions. This article describes the programs and reports on the educational outcomes of these computer uses.
14 citations
01 Mar 1989
TL;DR: In this article, it was shown that the principles of the special relativity can be realized not only on the Minkowskian spacetime but also on the spacetimes of non-zero constant curvature.
Abstract: We show that Einstein's principles of the special relativity can be realized not only on the Minkowskian spacetime but also on the spacetimes of non-zero constant curvature.
13 citations
13 citations
10 citations
TL;DR: The authors publicises some pedagogically interesting derivations, due to the late Professor Paul Kard of Tartu, Estonia, of certain formulae of relativistic kinematics and of the dependence of mass on speed.
Abstract: This article publicises some pedagogically interesting derivations, due to the late Professor Paul Kard of Tartu, Estonia, of certain formulae of relativistic kinematics and of the dependence of mass on speed.
01 Jan 1989
TL;DR: In this article, it was shown that the corresponding active coordinate transformations are not equal in general to the passive ones and that the composite active-passive transformations act on a space whose number of dimensions is ten (one-particle case) or larger (more than one particle).
Abstract: It has recently been shown by Vargas,(4) that the passive coordinate transformations that enter the Robertson test theory of special relativity have to be considered as coordinate transformations in a seven-dimensional space with degenerate metric. It has also been shown by Vargas that the corresponding active coordinate transformations are not equal in general to the passive ones and that the composite active-passive transformations act on a space whose number of dimensions is ten (one-particle case) or larger (more than one particle).
TL;DR: In this article, experiments designed to test special Relativity are reviewed and their capabilities of distinguishing Special Relativity from Absolute Space-Time theories are analyzed. But the results of these experiments are limited.
Abstract: Experiments designed to test Special Relativity are reviewed and their capabilities of distinguishing Special Relativity from Absolute Space-Time theories is analyzed. Of two specific forms of Absolute theories proposed in recent years, we show that one is refuted by past experiments while the other is still in contention.
TL;DR: The resolution of the Langevin paradox for an out-and-return journey gives rise to a result which appears to violate the underlying basis of special relativity as mentioned in this paper, leading to a physically-intelligible interpretation of Einstein's theory and reconciles it with the cosmologically-based fundamental reference frame revealed by modern astronomy.
Abstract: The resolution of the Langevin paradox for an out-and-return journey gives rise to a result which appears to violate the underlying basis of special relativity. The resolution of this second paradox, due to G. Builder, leads to a physically-intelligible interpretation of Einstein's theory and reconciles it with the cosmologically-based fundamental reference frame revealed by modern astronomy.
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TL;DR: The role played by coordinates in the formulation of an absolute spacetime theory is assessed in this paper, where it is shown that recent criticism on previous work of ours is wrong and the role of coordinates in spacetime theories is shown to be important.
Abstract: The role played by coordinates in the formulation of an absolute spacetime theory is assessed. It is shown that recent criticism on previous work of ours is wrong.
Dissertation•
01 Jan 1989
TL;DR: Bini et al. as discussed by the authors derived a compact analytical parametric approximate solution of Padé type which gives density curves and stellar radii in good accordance with already existing numerical results.
Abstract: The “effective geometry” formalism is used to study the perturbations of a white dwarf described as a self-gravitating fermion gas with a completely degenerate relativistic equation of state of barotropic type. The quantum nature of the system causes an absence of homological properties manifested instead by batropic stars and requires a parametric study of the solutions both at numerical and analytical level. We have explicitly derived a compact analytical parametric approximate solution of Padé type which gives density curves and stellar radii in good accordance with already existing numerical results. After validation of this new type of approximate solutions, we use them to construct the effective acoustic metric governing perturbations of any type following Chebsch’s formalism. Even in this quantum and relativistic case the stellar surface exhibits a curvature singularity due to the vanishing of density, as already evidenced in past studies on non relativistic and non quantum self-gravitating polytropic star. The equations of the theory are finally numerically integrated, in the simpler case of irrotational spherical pulsating perturbations including the effect of back-reaction, in order to have a dynamical picture of the process occurring in the acoustic metric. 10. Bini D., de Felice F., Geralico A., Accelerated orbits in black hole fields: the static case Classical and Quantum Gravity, vol. 28 225012, 2011. Abstract We study non-geodesic orbits of test particles endowed with a structure, assuming the Schwarzschild spacetime as background. We develop a formalism which allows one to recognize the geometrical characterization of those orbits in terms of their Frenet-Serret parameters and apply it to explicit cases as those of spatially circular orbits which witness the equilibrium under conflicting types of interactions. In our general analysis we solve the equations of motion offering a detailed picture of the dynamics having in mind a check with a possible astronomical set up. We focus on certain ambiguities which plague the interpretation of the measurements preventing one from identifying the particular structure carried by the particle. 11. Bini D., Geralico A., Jantzen R.T., Semeřák O.,
01 Mar 1989