A programmable quantum current standard from the Josephson and the quantum Hall effects

Poirier, W.; Lafont, F.; Djordjevic, S.; Schopfer, F.; Devoille, Laurent

doi:10.1063/1.4863341

Cited by 9 publications

(12 citation statements)

References 30 publications

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“…This would constitute a major step towards the realization of a universal and practical quantum generator/multimeter. More generally, the principle of using the PQCS as a reference for building the PQCG is seminal and can be exploited for other experiments or instruments [51]. For instance, a quantum current generator working in the AC regime can be developed using pulse-driven Josephson standards [55,56], AC QHRS [57] and current transformers [58].…”

Section: Discussionmentioning

confidence: 99%

“…A simple connection of the PJVS to the QHRS would not allow realizing U J /R H with the highest accuracy because of the large value of the two-wires series resistance (symbolized by r in Fig.1c) caused by the connecting links. A multiple series connection of the QHRS [50,51], a technique which exploits fundamental properties of the QHE, is implemented to reduce their effect. Each superconducting pad of the PJVS is connected to two QHRS terminals located along an equipotential edge of the Hall bar ( Fig.2a).…”

Section: A Realizationmentioning

confidence: 99%

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Practical Quantum Realization of the Ampere from the Elementary Charge

et al. 2016

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One major change of the future revision of the International System of Units is a new definition of the ampere based on the elementary charge 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 e, accurate to within 10 −8 in relative value and fulfilling traceability needs, is still missing despite the many efforts made 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 accurately quantized in terms of ef J (f J is the Josephson frequency) with measurement uncertainty of 10 −8 . This new quantum current source, which is 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. In addition, 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.

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Section: Discussionmentioning

confidence: 99%

Section: A Realizationmentioning

confidence: 99%

Practical Quantum Realization of the Ampere from the Elementary Charge

et al. 2016

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“…Very recently, a programmable quantum current generator (PQCG) based on the application of Ohm's law directly to the quantum voltage and resistance standards demonstrated quantized currents in terms of ef J (f J is a Josephson frequency) to within one part in 10 8 in the range from 1 µA up to a few mA [260,101]. This performance relies on the use of a cryogenic current comparator to detect and then amplify the current I PQCS flowing in a QHR multiply-connected to a PJVS, as shown in fig.27a.…”

Section: The Programmable Quantum Current Generatormentioning

confidence: 99%

“…The PQCG relies on the accurate exploitation by a CCC of a reference current I PQCS . This principle is seminal and can be applied to others devices [260]. One can cite the quantum ammeter ( fig.28a) based on the direct comparison of the current generated by a device under test (DUT) with the reference current.…”

Section: A New Ampere Metrologymentioning

confidence: 99%

The ampere and the electrical units in the quantum era

Poirier

Djordjevic

Schopfer

et al. 2019

Comptes Rendus. Physique

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By fixing two fundamental constants from quantum mechanics, the Planck constant h and the elementary charge e, the revised Système International (SI) of units endorses explicitly quantum mechanics. This evolution also highlights the importance of this theory which underpins the most accurate realization of the units. From 20 May 2019, the new definitions of the kilogram and of the ampere, based on fixed values of h and e respectively, will particularly impact the electrical metrology. The Josephson effect (JE) and the quantum Hall effect (QHE), used to maintain voltage and resistance standards with unprecedented reproducibility since 1990, will henceforth provide realizations of the volt and the ohm without the uncertainties inherited from the older electromechanical definitions. More broadly, the revised SI will sustain the exploitation of quantum effects to realize electrical units, to the benefit of end-users. Here, we review the state-of-the-art of these standards and discuss further applications and perspectives.

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“…In the reference loop, at the superconducting pads of the PJVS, quantized voltage steps, U J = n J f J K −1 J with K J = (2e/h), are generated when n J Josephson junctions are dc biased and driven at a microwave frequency f J . This voltage is applied to the QHRS through a double connection scheme [13,14]. Doing so, and thanks to the properties of the quantum Hall effect [14,13], the equivalent resistance R connected to the superconducting pads is equal to R = R H (1 + α), where R H is the quantum Hall resistance, which is equal to R K /2 at Landau level filling factor ν = 2 with R K = h/e 2 the von Klitzing constant, and where α = O((r/R H ) 2 ) is a second order correction due to the cable resistances r. This correction, which is significatively reduced compared to the usual first order correction of a simple connection corresponding to r/R H ∼ 3 × 10 −4 , can be determined with a relative uncertainty of a few parts in 10 9 .…”

Section: The Set-upmentioning

confidence: 99%

Improvements of the programmable quantum current generator for better traceability of electrical current measurements

Djordjevic,

Behr,

Drung

et al. 2021

Preprint

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A programmable quantum current generator based on the application of Ohm's law to quantum voltage and resistance standards has demonstrated a realization of the ampere from the elementary charge with a 10 −8 relative uncertainty [1]. Here, we report on improvements of the device leading to a noise reduction of the generated quantized current. The improved quantum current generator is used to calibrate different ammeters with lower measurement uncertainties. Besides, measurements of its quantized current using a calibrated Ultrastable Low-Noise Current Amplifier (ULCA) have shown that the realizations of the ampere at PTB (Physikalisch-Technische Bundesanstalt) and LNE (Laboratoire national de métrologie et d'essais) in the range ±50 µA agreed to -3.7 parts in 10 7 with a combined standard uncertainty of 3.1 parts in 10 7 (coverage factor k c = 1).

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A programmable quantum current standard from the Josephson and the quantum Hall effects

Cited by 9 publications

References 30 publications

Practical Quantum Realization of the Ampere from the Elementary Charge

Practical Quantum Realization of the Ampere from the Elementary Charge

The ampere and the electrical units in the quantum era

Improvements of the programmable quantum current generator for better traceability of electrical current measurements

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