Bulletin of the American Physical Society
2015 Annual Meeting of the APS Mid-Atlantic Section
Volume 60, Number 14
Friday–Sunday, October 23–25, 2015; Morgantown, West Virginia
Session AE1: Plenary IV |
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Chair: Aldo Romero, West Virginia University Room: Waterfront Hotel Salon E |
Sunday, October 25, 2015 11:30AM - 12:30PM |
AE1.00001: Measurements of the Planck constant and the revision of the SI Invited Speaker: Stephan Schlamminger The Planck constant, $h$, sets the scale for quantum mechanics. The uncertainties in measuring this constant have steadily declined in the last decades. Recently, two groups have reported results with relative uncertainties below 20 parts per billion. Such a precise knowledge of $h$ will allow us to use the Planck constant, together with the speed of light and the hyperfine structure of Cesium, to realize the unit of mass, the kilogram, at uncertainties not very different from the ones that we have from the artifact based definition. Hence, the time has come to change the definition of the unit of mass. This and other changes to our current system of units are proposed and might be implemented as early as 2018. In this talk, I will give you a brief overview of our current system of units, the proposed changes to it, and describe several experiments that measure the Planck constant. I will finally demonstrate a model of the NIST experiment to measure h constructed using Legos that can measure $h$ with a relative uncertainty of a few percent. [Preview Abstract] |
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