Plenary Presentation Details
Samuel Benz
NIST, Superconductive Electronics Group
PRESENTATION DAY AND TIME
Wednesday, September 9, 2026 | 8:00 a.m.
PRESENTATION TITLE
The Quantum Volt: How the Josephson Effect Revolutionized Standards and Measurement
ABSTRACT
The macroscopic quantum behavior of the Josephson effect has fundamentally transformed global measurement science, particularly within voltage metrology. Following the experimental verification of Josephson’s 1962 discovery, the effect was rapidly applied to voltage standards. However, 57 years elapsed before the International System of Units was officially redefined, allowing the Josephson voltage standard to realize the SI unit of the volt. Exploiting this quantum effect—while simultaneously advancing the materials and techniques required to fabricate superior, more reliable, and user-friendly circuits—has enabled novel measurement paradigms for voltage metrology and radio-frequency (RF) signal applications.
The most significant breakthroughs have occurred in voltage signal synthesis by exploiting the perfectly quantized pulses of Josephson junctions. These Josephson arbitrary waveform synthesizer (JAWS) systems generate AC voltage signals with unprecedented accuracy and precision. Furthermore, novel techniques have progressively extended JAWS capabilities to the higher frequencies required for RF communications. This presentation describes the breakthrough technologies that enabled unique Josephson circuit designs featuring advanced functionality and enhanced signal performance. These innovations in circuits and systems have continually improved DC and AC voltage measurements, electronic-based primary thermometry, and precision signal synthesis for RF communications.
I’ll demonstrate the quantum-locking range feature of Josephson circuits that guarantees the continuous production of quantum-accurate waveforms. I’ll review the specific and novel techniques developed to transfer signal accuracy from the cryogenic circuit to room-temperature devices. I’ll review the multiple reasons why Josephson voltage standard signals have been limited to frequencies below 20 GHz and describe some recent advancements that are finally allowing us to overcome the fundamental challenges of extending these quantum-accurate signals into the terahertz range.