The Quantum Revolution of the Metric System
Prof. William D. Phillips (Nobel Prize in Physics) (National Institute of Standards and Technology (NIST), USA)

On 20 May 2019 the International System of Units (the SI) experienced its most revolutionary change since the French revolution produced the metric system. Today, all of the base units of the SI are defined by fixing the values of constants of nature, resulting in a fundamentally quantum system of measurement units. This talk will discuss why such a reform was needed and how it is implemented.