Practical quantum realization of the ampere from the electron charge

Abstract

One major change of the future revision of the International System of Units (SI) is a new definition of the ampere based on the elementary charge \emph{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 \emph{e}, accurate to within $10^{-8}$ in relative value and fulfilling traceability needs, is still missing despite many efforts have been spent 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 quantized in terms of $e{f}_{\mathrm{J}}$ ($f_{\mathrm{J}}$ is the Josephson frequency) with a measurement uncertainty of $10^{-8}$. This new quantum current source, 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. Beyond, 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.

15 pages, 4 figures

References in corpus (4)

• CODATA Recommended Values of the Fundamental Physical Constants: 2014
• Quantum Hall resistance standards from graphene grown by chemical vapor deposition on silicon carbide
• Validation of a quantized-current source with 0.2 ppm uncertainty
• Validation of the ultrastable low-noise current amplifier as travelling standard for small direct currents

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• The ampere and the electrical units in the quantum era
• Optimization of quantized charge pumping using full counting statistics
• Improvements of the programmable quantum current generator for better traceability of electrical current measurements
• Spectral Signatures of Non-Trivial Topology in a Superconducting Circuit
• Heat and charge transport in interacting nanoconductors driven by time-modulated temperatures
• Electron shuttle as an autonomous single-electron source
• Advances toward high-accuracy gigahertz operation of tunable-barrier single-hole pumps in silicon
• Scalable Parallel Single-Electron Pumps in Silicon with Split-Source Control in the Nanoampere Regime