A7.3 - New developments for the programmable quantum current generator

J. Brun-Picard, D. Leprat, F. Schopfer +2 more

We report on the development of a programmable quantum current generator (PQCG) based on quantum voltage and resistance standards. First measurements with a digital amperemeter in the 100 μA range demonstrate the linearity of the generated current as a function of the theoretical current, linked to the electron charge, with a relative uncertainty of 2.7 × 10-7(k = 1). To overcome the detector limits and validate the PQCG as a practical realization of the ampere in the new SI, accurate quantization measurements with a target combined uncertainty of a few parts in 108are in progress.

Vladimír Bužek, Mark S. Hillery, Mário Ziman +1 more

S. P. Giblin, E. Mykkänen, A. Kemppinen +7 more

Mark W. Keller, José Aumentado

One major change of the future revision of the International System of Units is a new definition of the ampere based on the elementary charge e. Replacing the former definition based on Ampère's force law will allow one to fully benefit from quantum physics to realize the ampere.However, a quantum realization of the ampere from e, accurate to within 10 -8 in relative value and fulfilling traceability needs, is still missing despite the many efforts made for the development of single-electron tunneling devices.Starting again with Ohm's law, applied here in a quantum circuit combining the quantum Hall resistance and Josephson voltage standards with a superconducting cryogenic amplifier, we report on a practical and universal programmable quantum current generator.We demonstrate that currents generated in the milliampere range are accurately quantized in terms of ef J (f J is the Josephson frequency) with measurement uncertainty of 10 -8 .This new quantum current source, which is able to deliver such accurate currents down to the microampere range, can greatly improve the current measurement traceability, as demonstrated with the calibrations of digital ammeters.In addition, it opens the way to further developments in metrology and in fundamental physics, such as a quantum multimeter or new accurate comparisons to single-electron pumps.

W. P. Kirk

J. Brun-Picard, S. Djordjevic, D. Leprat +2 more

One major change of the future revision of the International System of Units is a new definition of the ampere based on the elementary charge e. Replacing the former definition based on Ampère's force law will allow one to fully benefit from quantum physics to realize the ampere.However, a quantum realization of the ampere from e, accurate to within 10 -8 in relative value and fulfilling traceability needs, is still missing despite the many efforts made for the development of single-electron tunneling devices.Starting again with Ohm's law, applied here in a quantum circuit combining the quantum Hall resistance and Josephson voltage standards with a superconducting cryogenic amplifier, we report on a practical and universal programmable quantum current generator.We demonstrate that currents generated in the milliampere range are accurately quantized in terms of ef J (f J is the Josephson frequency) with measurement uncertainty of 10 -8 .This new quantum current source, which is able to deliver such accurate currents down to the microampere range, can greatly improve the current measurement traceability, as demonstrated with the calibrations of digital ammeters.In addition, it opens the way to further developments in metrology and in fundamental physics, such as a quantum multimeter or new accurate comparisons to single-electron pumps.