A current-generating device could allow for unprecedented precision in implementing a proposed redefinition of the ampere, the standard unit of current.
Under the International System of Units (SI), the ampere is defined as the amount of current that generates a certain mechanical force between two wires. However, the experimental setup required to produce this current leads to uncertainties. Wilfrid Poirier and his colleagues at the National Metrology and Testing Laboratory in Trappes, France, developed a device that exploits quantum effects to manipulate electrons. In this way, they generated a wide range of reference currents with a precision of a few parts per 100 million.
Their work could allow the ampere to be realized more accurately in terms of electron charge in an SI revision scheduled for 2018.