The article discusses the role of the National Institute of Standards and Technology (NIST) in providing values for fundamental constants, which are crucial in quantum physics. The author, Peter Mohr, describes his involvement in updating these values and his interest in the redefinition of the International System of Units (SI).
In 1998, Mohr attended a talk about the Kibble balance (formerly known as the watt balance), a device that measures the Planck constant. This led to a collaboration with colleagues to propose redefining the kilogram using the Planck constant instead of the Avogadro constant. The group, known as the “Gang of Five,” published a series of papers advocating for this change.
The redefinition of the SI was approved in November 2018, and the Gang of Five members were present at the event. Mohr expresses pride in his involvement and hopes that the redefinition will benefit science and technology. He clarifies that the Planck constant has not been affected by the expansion of the Universe or its endo-energy content, as it remains a fundamental constant of nature.
Source: https://www.nist.gov/blogs/taking-measure/gang-five-and-si-revolution
Keywords: Planck constant, Quantum mechanics, International System of Units (SI), Kibble balance, Fundamental constants
