Realization of the quantum ampere using the quantum anomalous Hall and Josephson effects
Jul 31, 2023Citations per year
Abstract: (arXiv)
By directly coupling a quantum anomalous Hall resistor to a programmable Josephson voltage standard, we have implemented a quantum current sensor (QCS) that operates within a single cryostat in zero magnetic field. Using this QCS we determine values of current within the range 9.33 nA - 252 nA, providing a realization of the ampere based on fundamental constants and quantum phenomena. The relative Type A uncertainty is lowest, 2.30 10 A/A, at the highest current studied, 252 nA. The total root-sum-square combined relative uncertainty ranges from 3.91 10 A/A at 252 nA to 41.2 10 A/A at 9.33 nA. No DC current standard is available in the nanoampere range with relative uncertainty comparable to this, so we assess our QCS accuracy by comparison to a traditional Ohm's law measurement of the same current source. We find closest agreement (1.46 4.28)10 A/A for currents near 83.9 nA, for which the highest number of measurements were made.Note:
- 12 pages, 5 figures, 15 pages of supplemental information
References(50)
Figures(14)
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