Sur une définition géométrique du tenseur d'énergie d'Einstein AND Sur une généralisation de la notion de courbure de Riemann et les espaces à torsion AND Sur les espaces généralisés et la théorie de la Relativité AND Sur les espaces conformes généralisés et l'Univers optique AND Sur les équations de structure des espaces généralisés et l'éxpression analytique du tenseur d'Einstein in Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences 174, 1922, pp.437-439, 593-595, 734-737, 857-60, 1104-1107 [FIVE PAPERS, EINSTEIN-CARTAN THEORY]

Paris: Gauthier-Villars, 1922. 1st Edition. FIRST EDITION OF THE FIVE PAPERS THAT COMPRISE THE EINSTEIN-CARTAN THEORY OF GRAVIATION (ECT).

"In theoretical physics, the Einstein-Cartan theory is a classical theory of gravitation similar to general relativity, but relaxing the assumption that the affine connection has vanishing antisymmetric part (torsion tensor), so that the torsion can be coupled to the intrinsic angular momentum (spin) of matter, much in the same way in which the curvature is coupled to the energy and momentum of matter. In fact, the spin of matter in curved spacetime requires that torsion is not constrained to be zero but is a variable in the principle of stationary action. Regarding the metric and torsion tensors as independent variables gives the correct generalization of the conservation law for the total (orbital plus intrinsic) angular momentum to the presence of the gravitational field.

"Einstein-Cartan theory has been historically overshadowed by its torsion-free counterpart and other alternatives like Brans-Dicke theory because torsion seemed to add little predictive benefit at the expense of the tractability of its equations. Since the Einstein-Cartan theory is purely classical, it also does not fully address the issue of quantum gravity. In the Einstein-Cartan theory, the Dirac equation becomes nonlinear and therefore the superposition principle used in usual quantization techniques would not work.

Recently, interest in Einstein-Cartan theory has been driven toward cosmological implications, most importantly, the avoidance of a gravitational singularity at the beginning of the universe. The theory is considered viable and remains an active topic in the physics community" (Wikipedia). CONDITION & DETAILS: Complete volume. Ex-libris bearing only a deaccessioned stamp on the back of the title page and slight ghosting at the spine where a spine level has been removed. 4to (11 x 8 inches; 275 x 200mm). [2], 1816, [2]. Bound in clean full blue cloth, gilt-lettered at the spine; ghosting from the removal of a label at the spine; stamp on the rear of the title page. Solidly and tightly bound. Very occasional toning, otherwise clean and bright throughout. Very good condition.