Topic
Four-force
About: Four-force is a research topic. Over the lifetime, 3459 publications have been published within this topic receiving 87308 citations.
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01 May 1961
TL;DR: In this paper, an analogy between electromagnetism and gravitation is presented which allows calculation of various gravitational forces by considering the equivalent electromagnetic problem, and justification for the analogies is given.
Abstract: Einstein's general theory of relativity is broken down and simplified under limitations usually satisfied in experimentally realizable situations. Following the work of Moller,1 an analogy between electromagnetism and gravitation is presented which allows calculation of various gravitational forces by considering the equivalent electromagnetic problem. A number of examples are included. Tensor formulation is not used except in the Appendix, where justification for the analogies is given.
79 citations
TL;DR: The 3rd rank tensor of hypermomentum was introduced in this article, and a general relativistic field theory of energy-momentums and hypermoments is outlined.
Abstract: Abstract In this series of notes, we introduce a new quantity into the theory of classical matter fields. Besides the usual energy-momentum tensor, we postulate the existence of a further dynamical attribute of matter, the 3rd rank tensor ⊿ijk of hypermomentum. Subsequently, a general relativistic field theory of energy-momentum and hypermomentum is outlined. In Part I we motivate the need for hypermomentum. We split it into spin angular momentum, the dilatation hypermomentum, and traceless proper hypermomentum and discuss their physical meanings and conservation laws.
79 citations
Posted Content•
TL;DR: Shape Dynamics (SD) is a new theory of gravity that is based on fewer and more fundamental first principles than General Relativity (GR) The most important feature of SD is the replacement of GR's relativity of simultaneity with a more tractable gauge symmetry, namely invariance under spatial conformal transformations.
Abstract: Shape Dynamics (SD) is a new theory of gravity that is based on fewer and more fundamental first principles than General Relativity (GR) The most important feature of SD is the replacement of GR's relativity of simultaneity with a more tractable gauge symmetry, namely invariance under spatial conformal transformations This Tutorial contains both a quick introduction for readers curious about SD and a detailed walk-through of the historical and conceptual motivations for the theory, its logical development from first principles and an in-depth description of its present status The Tutorial is sufficiently self-contained for an undergrad student with some basic background in GR and Lagrangian/Hamiltonian mechanics It is intended both as a reference text for students approaching the subject and as a review for researchers interested in the theory
79 citations
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01 Dec 2004
TL;DR: In this paper, the authors argue that the assumption that there could be superluminal signals in relativity gives rise to well-known paradoxes, and that this situation is not nearly as dire as it appears at first sight.
Abstract: It is widely believed that relativity -- both special and general -- requires that no physical signal travel at a speed faster than that of light. For instance, the assumption that there could be superluminal signals in relativity gives rise to well-known paradoxes. We suggest that this situation is not nearly as dire as it appears at first sight. Indeed, we shall argue that relativity is virtually as viable and self-consistent as a physical theory in the presence of superluminal signals as it is with such signals excluded.
79 citations