An ac quantum voltmeter based on a 10 V programmable Josephson array

TLDR

Develop an ac quantum voltmeter based on a 10 V programmable Josephson array that is simple to use, provides dc and ac calibration up to the kHz range, and ensures direct traceability to a quantum standard. The voltmeter employs a 10 V programmable Josephson array and software control to perform calibrations up to 7 VRMS from dc to 10 kHz. The device matches conventional Josephson standards at dc, extends performance to 10 kHz, achieves <2 × 10⁻¹⁰ relative uncertainty at dc and <1.7 µV/V at 1 kHz for 1 min, and is robust for general metrology laboratories.

Abstract

An ac quantum voltmeter based on a 10 V programmable Josephson array that is simple to use, provides dc and ac calibration up to kHz range for equipment widely used in metrology, and ensures direct traceability to a quantum-based standard, is developed. This ac quantum voltmeter is proven to match conventional Josephson standard systems at dc and extends its advantages up to 10 kHz in the low-frequency ac range. The ac quantum voltmeter is capable of performing calibrations up to 7 VRMS in the frequency range from dc to 10 kHz completely under software control. A direct comparison at dc has demonstrated an uncertainty better than 2 parts in 1010 (k = 2). The uncertainty at 1 kHz is better than 1.7 µV V−1 (k = 2) for a measurement time of 1 min. The ac quantum voltmeter is a robust and practical system that fulfils the needs of general metrology laboratories for quantum-based voltage calibrations.