Presently, Planck’s constant is a fundamental constant that can not be derived from other onstants. Assis developed a model based on an extended Weber-type potential energy, that allows calculating gravitational-type forces from neutral oscillating electric dipoles. Here we show that the maximum possible point-mass in his model equals the Planck mass which allows us to derive Planck’s constant and the fine-structure constant. We match the exact order of magnitude only requiring a pre-factor that is present in all Weber-type theories and has to be determined empirically. This classical model allows to link electromagnetic, gravitational and quantum properties with one approach.

Presently, Planck’s constant is a fundamental constant that can not be derived from other onstants. Assis developed a model based on an extended Weber-type potential energy, that allows calculating gravitational-type forces from neutral oscillating electric dipoles. Here we show that the maximum possible point-mass in his model equals the Planck mass which allows us to derive Planck’s constant and the fine-structure constant. We match the exact order of magnitude only requiring a pre-factor that is present in all Weber-type theories and has to be determined empirically. This classical model allows to link electromagnetic, gravitational and quantum properties with one approach.

Dans l'optique d'une modification du Système international d'unités (SI) fondée sur la valeur de constantes fondamentales de la physique, le Laboratoire national de métrologie et d'essais (LNE) a développé une expérience de balance du watt de manière à participer à la redéfinition de l'unité de masse : le kilogramme. Cette unité est en effet la dernière des unités de base du SI qui repose encore sur un artefact matériel : le prototype international du kilogramme.Une bobine circulaire, plongée dans un flux magnétique radial et horizontal est le coeur du dispositif de la balance du watt. Parcourue par un courant (phase statique), il s'exerce sur elle une force de Laplace nominalement verticale qui est comparée au poids d'une masse étalon. Déplacée de manière nominalement verticale (phase dynamique), il apparaît à ses bornes une tension.Il résulte de la combinaison de ces deux étapes l'égalité d'une puissance électrique et d'une puissance mécanique virtuelles. La détermination des grandeurs électriques par comparaison à l'effet Josephson et à l'effet Hall quantique permet d'établir une relation entre une masse macroscopique et la constante de Planck.Après une dizaine d'années de développements séparés des différents éléments, de très nombreuses caractérisations et améliorations, les premiers travaux de cette thèse ont consisté en l'assemblage des sous-ensembles de la balance du watt.Nous nous sommes ensuite intéressés à l'évaluation des composantes principales d'incertitudes et notamment à celles liées aux problématiques d'alignement : en particulier l'alignement sur la verticale des faisceaux lasers des interféromètres mesurant la vitesse de la bobine, l'alignement sur l'horizontale des pivots du comparateur de forces, et enfin l'évaluation des forces de Laplace horizontales et des moments parasites s'exerçant sur la bobine et leurs influences sur la détermination de la constante de Planck.Une valeur de la constante de Planck a été déterminée à l'été 2014, qui conduit à h=6,6260688(20)E-34 Js, évaluation dont l'incertitude-type relative est 3.1E-7. Des propositions pour améliorer cette incertitude sont avancées. / In the pespective of a modification of the Système international of units (SI) based on value of fondamental constants of physics, the Laboratoire national de métrologie et d'essais (LNE) has developped a watt balance experiment, in order to contribute to the redefinition of the unit of mass: the kilogramm. Indeed, this unit is the last one of the base units of the SI which is based on a material artefact: the international prototype of kilogram.A circular coil, immersed in a horizontal and radial magnetic flux is the centre of the watt balance device. Flown by a current (static phase), it exerts on it a nominaly vertical Laplace force which is compared to the weight of a standard mass. Moved nominally vertically (dynamic phase), it appears at its terminals a voltage.It results from the combination of these two steps an equality of virtual electric and mechanical powers. The determination of electrical quantities compared to the Josephson effect and to the quantum Hall effect establishes a relationship between macroscopic mass and the Planck constant.After separate developments of the different elements with continuous characterizations and improvements, the entire system has been assembled, the first works of this thesis consisted in assembling subsets of the watt balance.Then, we have evaluated the main components of uncertainties, especially those related to the alignment issues: alignment relative to the vertical of the laser beam interferometers which measure the velocity of the coil, alignment with horizontal of the pivots from the beam of the forces comparator and finally the evaluation of horizontal Laplace forces and parasitic moments acting on the coil and their influences on determining Planck's constant.A determination of the Planck constant was then carried out in the summer of 2014, which leads to the value h=6.6260688(20)E-34 Js. The relative standard uncertainty associated is 3.1E-7. Proposals to improve this uncertainty are advanced.

The Planck constant is one of the most important constants in nature, as it describes the world governed by quantum mechanics. However, it cannot be derived from other natural constants. We present a model from which it is possible to derive this constant without any free parameters. This is done utilizing the force between two oscillating electric dipoles described by an extension of Weber electrodynamics, based on a gravitational model by Assis. This leads not only to gravitational forces between the particles but also to a newly found Casimir-type attraction. We can use these forces to calculate the maximum point mass of this model which is equal to the Planck mass and derive the quantum of action. The result hints to a connection of quantum effects like the Casimir force and the Planck constant with gravitational ones and the origin of mass itself.

The Planck constant is one of the most important constants in nature, as it describes the world governed by quantum mechanics. However, it cannot be derived from other natural constants. We present a model from which it is possible to derive this constant without any free parameters. This is done utilizing the force between two oscillating electric dipoles described by an extension of Weber electrodynamics, based on a gravitational model by Assis. This leads not only to gravitational forces between the particles but also to a newly found Casimir-type attraction. We can use these forces to calculate the maximum point mass of this model which is equal to the Planck mass and derive the quantum of action. The result hints to a connection of quantum effects like the Casimir force and the Planck constant with gravitational ones and the origin of mass itself.