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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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Journal ArticleDOI
TL;DR: Conditions are found for the existence of integral constraints on stress-energy perturbations in general relativity using a vector field V, and the Robertson-Walker spacetimes are shown to have such constraint vectors.
Abstract: Conditions are found for the existence of integral constraints on stress-energy perturbations in general relativity. The integral constraints can be thought of as a general-relativistic generalization of the conservation of energy and momentum of matter perturbations in special relativity. The constraints are stated in terms of a vector field V\ensuremath{\rightarrow}, and the Robertson-Walker spacetimes are shown to have such constraint vectors. Although in general V\ensuremath{\rightarrow} is not a Killing vector, in a vacuum spacetime the constraint vectors are precisely the Killing vectors.

66 citations

Journal ArticleDOI
TL;DR: Deformed special relativity is embedded in deformed general relativity using the methods of canonical relativity and loop quantum gravity as mentioned in this paper, which in some regimes can be rewritten as nonlinear Poincar\'e algebras with momentum-dependent deformations of commutators between boosts and time translations.
Abstract: Deformed special relativity is embedded in deformed general relativity using the methods of canonical relativity and loop quantum gravity. Phase-space dependent deformations of symmetry algebras then appear, which in some regimes can be rewritten as nonlinear Poincar\'e algebras with momentum-dependent deformations of commutators between boosts and time translations. In contrast to deformed special relativity, the deformations are derived for generators with an unambiguous physical role, following from the relationship between canonical constraints of gravity with stress-energy components. The original deformation does not appear in momentum space and does not give rise to nonlocality issues or problems with macroscopic objects. Contact with deformed special relativity may help to test loop quantum gravity or restrict its quantization ambiguities.

66 citations

Book
01 Jan 1976

66 citations

Posted Content
TL;DR: In this article, it was shown that the normalized Lorentzian state sum is finite on any triangulation, and thus provides a candidate for a perturbatively finite quantum theory of general relativity in four dimensions with Lorentziian signature.
Abstract: We show that the normalized Lorentzian state sum is finite on any triangulation. It thus provides a candidate for a perturbatively finite quantum theory of general relativity in four dimensions with Lorentzian signature.

65 citations

Journal ArticleDOI
TL;DR: The parametrized post-Newtonian parameter (which identically vanishes in general relativity) plays a dual role in that it is associated both with a violation of the momentum conservation law and with the existence of a preferred frame as mentioned in this paper.
Abstract: General relativity predicts that energy and momentum conservation laws hold and that preferred frames do not exist. The parametrized post-Newtonian formalism phenomenologically quantifies possible deviations from general relativity. The parametrized post-Newtonian parameter (which identically vanishes in general relativity) plays a dual role in that it is associated both with a violation of the momentum conservation law and with the existence of a preferred frame. By considering the effects of in certain binary pulsar systems, it is shown that (90% CL). This limit improves on previous results by several orders of magnitude, and shows that pulsar tests of rank (together with Hughes - Drever-type tests) among the most precise null experiments of physics.

65 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20239
202211
20208
20193
20185
201756