The article discusses the new definition of the ampere, one of the base units in the International System of Units (SI). The new definition ties the ampere directly to the elementary electric charge, which is approximately 1.602176634 × 10^-19 coulombs. This makes the ampere definition more straightforward and directly related to a fundamental constant of nature.
However, realizing this new definition in practice is challenging. Single-electron transport (SET) techniques are being developed to count individual electrons and create a current. While SET can count up to 100 million electrons per second with uncertainties of a few parts in a hundred million, this is still far from the required 10^18 electrons per second for a full ampere.
Researchers are working on improving SET techniques and developing other methods to realize the new ampere definition. While significant challenges remain, the article suggests that a practical quantum-based ampere standard will eventually be achieved.
Source: https://www.nist.gov/si-redefinition/ampere-future
Keywords: ampere, electron, elementary charge, standard, metrology
