You are here: Home / Seminars / Seminar Database / "A New Kilogram in 2018!? How Low-dimensional Electron Systems Contributed to this Development"

"A New Kilogram in 2018!? How Low-dimensional Electron Systems Contributed to this Development"

Main Content

Klaus von Klitzing, Max Planck Institute for Solid State Research
When
31 July 2017 from 6:00 PM to 7:00 PM
Where
Heritage Hall, HUB-Robeson Center
Add event to calendar
vCal
iCal

Measurements are an integral part of our everyday life, and the International System of Units (SI units) forms the basis for all measurements. Many units are now defined in terms of fundamental constants of nature, so they may be universally reproducible. For example atomic frequencies are used for the time (atomic clock) and the meter is defined as the distance traveled by light in vacuum in 1/299,792,458 seconds, which corresponds to a fixed value for the velocity of light. The kilogram, the unit of mass, has remained an exception. To this day, a kilogram is equal, by definition, to the mass of a prototype kept in an obscure, securely guarded laboratory at the Bureau International des Poids et Mesures in Sevres, France. Long-term comparisons of the kilogram prototype with other mass standards indicate that the mass of the prototype is not stable with time. Therefore, the General Conference on Weights and Measures published at its last meeting in November 2014 a resolution recommending definition of the mass in terms of invariants of nature. I will show in this talk how the quantized Hall resistance (Nobel Prize 1985) can be used not only for the realization of a resistance standard, but also for a new realization of a kilogram by comparing electrical and mechanical forces with the so-called Kibble balance. 

 

Seminars