https://doi.org/10.1140/epjc/s10052-017-5452-y
Regular Article - Theoretical Physics
Generalization of Einstein’s gravitational field equations
Département de Physique, Ecole Normale Supérieure Paris-Saclay, 61 av du président Wilson, 94235, Cachan, France
* e-mail: frederic.moulin@ens-paris-saclay.fr
Received:
2
November
2017
Accepted:
5
December
2017
Published online:
16
December
2017
The Riemann tensor is the cornerstone of general relativity, but as is well known it does not appear explicitly in Einstein’s equation of gravitation. This suggests that the latter may not be the most general equation. We propose here for the first time, following a rigorous mathematical treatment based on the variational principle, that there exists a generalized 4-index gravitational field equation containing the Riemann curvature tensor linearly, and thus the Weyl tensor as well. We show that this equation, written in n dimensions, contains the energy-momentum tensor for matter and that of the gravitational field itself. This new 4-index equation remains completely within the framework of general relativity and emerges as a natural generalization of the familiar 2-index Einstein equation. Due to the presence of the Weyl tensor, we show that this equation contains much more information, which fully justifies the use of a fourth-order theory.
© The Author(s), 2017
