Quantum project publishes paper in Nature journal

Developing quantum electric current standards to underpin digital transformation

The accurate measurement of small electrical currents has many applications in areas such as environmental monitoring, energy efficiency, climate research, nuclear safety, medical applications and digital transformation. The long-term progress in these areas and increasingly demanding European goals and regulations need to be backed with the reliable measurement of electrical currents. Ensuring the highest possible accuracy and stability for these measurements requires the provision of primary quantum standards.

To fully unleash the potential of single charge control for quantum metrology and technology, Metrology Partnership project Advanced quantum technology for metrology of electrical currents (AQuanTEC, 23FUN05) is working to develop a robust primary quantum standard for electrical current, and explore novel device concepts exploiting technological advances driven by solid state quantum technology research.

In electrical quantum metrology, the prime examples of robust primary quantum standards are the Josephson voltage standard and the quantum Hall resistance standards, which directly exploit the definition of the International System of Units, the SI, using fundamental constants.

Nature Communications publication

As part of the work of the project, LNE, the French National Metrology Institute, has developed an improved version of a programmable quantum current generator. This device combines the quantum Hall effect and a programmable quantised Josephson voltage source in series with a cryogenic current comparator to generate a quantised current. The improved version now allows the generation of a quantised current down to microampere level with a record uncertainty lower than one part in 108. This is an improvement of more than one order of magnitude, which was used to calibrate commercial ammeter with uncertainties only limited by the device under test. These calibrations will enable ammeters to be compared. Quantised low currents could also be used to calibrate a resistor of large resistance value (1 MW) by comparison of its voltage to that of a Josephson standard.

These research results have been published in the high impact journal Nature Communications:

A primary quantum current standard based on the Josephson and the quantum Hall effects

Project coordinator Frank Hohls from PTB said

‘Electronic devices and sensors are ubiquitous in our life. Their development and their functionality often depend on traceable measurements of small electrical currents. The demonstrated primary quantum current source with utmost accuracy will allow R&D engineers to strive towards new or improved devices and applications based on improved measurement capabilities.’.

This Metrology Partnership project has received funding from the European Partnership on Metrology, co-financed by the European Union Horizon Europe Research and Innovation Programme and from the Participating States.

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