Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)

Nov. 8, 2019 at 2 p.m. c.t. in Lorentz-Raum (05-127), Staudingerweg 7Prof. Dr. Peter van Loock

Institut für Physik

loock@uni-mainz.de

Dr. Lars von der Wense

Institut für Physik

lars.vonderwense@uni-mainz.de

Dr. Stephan Schlamminger (National Institute of Standards and Technology, Gaithersburg, USA)

Up to May 20th this year, there was one mass on earth that we knew with absolute precision, i.e., zero uncertainty. This mass was the international prototype of the kilogram. Since May 20th, it is just another mass and thew mass unit is now defined via a fixed value of the Planck constant, h=6.62607015×〖10〗^(-34) "J s" with zero uncertainty. In this presentation, I will explain how the unit of mass can be realized at the kilogram scale via the Kibble balance and the X-ray crystal density method. In the present SI, it is, however, no longer necessary to realize the unit at the cardinal point of 1 kg, it can be realized at any scale. The talk will present some future possibilities of this scale invariant definition of the mass unit.