Search arXiv⌕ Search

arXiv · gr-qc/0410068

A Strange Detail Concerning the Variational Principle of General Relativity Theory

Abstract

A mathematical complication due to an unnecessary formal assumption concerning the variational principle of general relativity theory, which apparently bothered Einstein and Hilbert, is shown and cleared up. Some historical confusion seems caused by the impossibility to use the conventional Euler-Lagrange formalism directly there, which even otherwise is nothing but one of various possible procedures to apply the superior principle of least action. Correspondingly to the absence of any direct calculation in the literature so far, only a numerical modification in parts - explicitly taken into account now after once mentioned by Hilbert without implementation - would allow to compute the fundamental Einstein tensor density from these authors' initial formulae, which must not be taken literally. Nevertheless adhering to a merely symbolic Euler-Lagrange formalism, this needs a clear distinction between 'component differentiation' and 'tensor differentiation' defined here. Various corresponding solutions are shown including the probably most natural one. Two of them are additionally verified in the detailed supplementary material appended to the electronic edition of the note.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Peter Ostermann. 2014-02-11. A Strange Detail Concerning the Variational Principle of General Relativity Theory. https://arxiv.org/abs/gr-qc/0410068

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

An upper bound on the minimum orbital period of black holes

Previous research has focused on establishing lower bounds on the minimum orbital period of black holes. In this work, we explore the complementary question of whether an upper bound exists for the minimum orbital period of black holes. We investigate the minimum orbital periods of three types of black holes: Schwarzschild, Reissner-Nordström and Kerr-Newman black holes. We find that the minimum orbital period of these black holes is bounded by an upper limit $T_{min} \leqslant 6\sqrt{3}πM$, where $M$ is the black hole mass. Our results suggest that this upper bound on the minimum orbital period may be a general property in black hole spacetimes.

gr-qc↗

Bounds on the minimum orbital period in the background of 5-dimensional charged black holes

In this paper, we study the upper and lower bounds on the minimum orbital period of 5-dimensional charged black holes. Our results indicate that the upper bound of the minimum orbital period corresponds to non-charged black holes, while the lower bound is achieved in the case of maximally charged black holes. We further establish precise analytical expressions for the upper and lower bounds of the minimum orbital period. Our findings provide valuable insights into 5-dimensional charged black holes and help constrain theoretical gravity models.

gr-qc↗

Analysis of minimum orbital periods around d-dimensional charged black holes

This paper investigates the bounds on the minimum orbital period for test objects around d-dimensional charged black holes in asymptotically flat spacetimes. We derive the exact critical radius and the minimum orbital period. We then prove analytically that the minimum orbital period decreases strictly as the charge of the black hole increases. Thus, the upper limit is reached for an uncharged black hole, while the lower limit is attained for a maximally charged one, and the two bounds take the closed form $\frac{2π(d-2)}{d-3}[(d-2)M]^{\frac{1}{d-3}}\leqslant T_{min} \leqslant 2π\sqrt{\frac{d-1}{d-3}}\,[(d-1)M]^{\frac{1}{d-3}}$. Since the minimum period equals $2π$ times the shadow radius, the upper bound is equivalently a universal upper bound on the shadow radius. These results improve our understanding of dynamics around d-dimensional black holes and impose constraints on candidate gravity theories.

gr-qc↗