Dual radiofrequency drive quantum voltage standard with nanovolt resolution based on a closed-loop refrigeration cycle

Georgakopoulos, D.; Budovsky, I.; Hagen, Thomas; Sasaki, Hirokazu; Yamamori, Hirotake

doi:10.1088/0957-0233/23/12/124003

Cited by 6 publications

(7 citation statements)

References 18 publications

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“…The PD JJAs can produce very low dc voltages (theoretically less than 1 nV, but the lowest voltages are practically limited by noise to less than 10 nV at present) without the need of long pulse patterns, hence the memory requirements of the pattern generators for the PD JJAs are minimal. Also, simple and low computational load algorithms (worst case scenario, three comparisons, one subtraction, five multiplications, and one addition) can be used to generate the voltages, compared to the dual CWD JJAs described in [23]. The last two features make the system suitable for use in the feedback loop of a slow control system (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…Another approach to generate dc voltages with low uncertainty that is based on the use of two PJVS chips having two different RF drives was proposed in [22] and implemented in [23][24][25][26]. This approach can produce quasi-continuous voltages up to 10 V and is effective even in systems having a few imperfect junctions per PJVS chip [26].…”

Section: Introductionmentioning

confidence: 99%

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Quasi-continuous dc voltage standard using sinusoidal and pulse-driven Josephson junction arrays

Georgakopoulos¹,

Budovsky²,

Benz³

2022

Meas. Sci. Technol.

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Josephson voltage standards (JVSs) provide a primary realization of the volt, the unit of electromotive force. They generate direct (dc) voltages up to 10 V and show agreement better than 1 nV/V at 10 V. For JVSs based on Josephson junction arrays (JJAs) that are driven by sinusoidal radiofrequency (RF) power, commonly referred to as continuous wave-driven JJAs (CWD JJAs), the minimum voltage that can be generated is limited to the voltage across one Josephson junction for practical devices. To achieve this resolution, they may require a perfect JJA chip. JVSs based on a pulse-driven (PD) JJA require high performance electronics (i.e., high bandwidth, low distortion and jitter, pulse shaping filters and large memory) to achieve their minimum and maximum voltage. We have combined two CWD JJAs and two PD JJAs driven by two microwave inputs to one chip to generate quasi-continuous dc voltages up to the sum of the full-scale voltages of both JJAs that are robust to the imperfections of the Josephson junctions and have relaxed requirements on the radio frequency (RF) electronics driving the JJA, compared to the existing CWD JVSs and PD JVSs, respectively. By use of the JJA chip at the National Measurement Institute Australia, we demonstrate its feasibility to generate voltages up to 1 V. Preliminary evaluation of the system shows that the voltage uncertainty can be 11 nV (k=2) or better and the theoretical resolution is better than 1 nV from 0 V to 1 V. The main requirement is that all the Josephson junctions must have quantum locking ranges with respect to the power and frequency of the RF bias and for the PD JJAs to have a constant voltage over a range of dc bias current. Although this development is not a replacement for existing state-of-the-art JVSs, we anticipate that it will be an alternative fit-for-purpose solution for metrological applications under non-ideal operating conditions or when the components of the state-of-the-art solutions are not available.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quasi-continuous dc voltage standard using sinusoidal and pulse-driven Josephson junction arrays

Georgakopoulos¹,

Budovsky²,

Benz³

2022

Meas. Sci. Technol.

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“…RESULTS The results reported in this section are based on the electronics of the dual RF drive PJVS reported in [4]. The bias source of this system can bias two PJVSs of 12 segments each.…”

Section: Modified Simulated Annealing Algorithmmentioning

confidence: 99%

“…This technique is particularly useful for low voltages and can produce higher voltages than conventional PJVS, but compared with the conventional PJVSs, it is more complex. At the National Measurement Institute, Australia, we have implemented such a scheme [4], [5] for voltages up to 10 V and extended the algorithms to the case where each segment of the PJVS can contain an arbitrary number of junctions. This allows the use of an imperfect PJVS, with missing junctions or segments, to achieve the same voltage resolution as a dual RF drive PJVS containing two perfect arrays.…”

Section: Introductionmentioning

confidence: 99%

“…We have presented the operation and the challenges involved in the physical realization of such a system in [4] and its metrological applications in [5]. This paper, which is an extension of [6], focuses on the mathematical methods used to maximize the voltage resolution in a specified voltage range, describes two general algorithms that can be used to solve such a problem for a wide range of voltages, and reports on their performance.…”

Section: Introductionmentioning

confidence: 99%

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Maximizing the Resolution of a Dual RF Drive Programmable Josephson Voltage Standard

Georgakopoulos

2015

IEEE Trans. Instrum. Meas.

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A dual radio frequency drive programmable Josephson voltage standard can generate quasi-continuous voltages with quantum accuracy. This paper focuses on the mathematical methods used to maximize the achievable voltage resolution and describes two algorithms that can be employed. Quasi-continuous voltages with a resolution of a few nanovolts have been achieved using Josephson junction arrays with missing junctions and an almost arbitrary segment structure.Index Terms-Josephson standards, mixed integer programming, quantum electrical standards, voltage standards.

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Automated direct comparison of two cryocooled 10 volt programmable Josephson voltage standards

et al. 2018

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We have performed direct dc comparisons between two cryocooled 10 V programmable Josephson voltage standards. Utilizing an automated synchronization scheme for the voltage reversals enables use of a high-sensitivity analog null detector on its 10 µV range. No switches or manual operations are necessary to protect the null detector from overload signals. The agreement measured between the two voltage standards at 10 V is 9 parts in 1012 with a relative combined uncertainty of 29 pV V−1 (k = 2 coverage factor). Since both systems can be operated floating from ground, various grounding configurations of the measurement circuit were investigated to evaluate possible leakage current paths to ground. Comparing the two systems under various grounding conditions enables minimization of leakage-current errors, optimization of system performance by revealing leakage-limiting components, and verification of key elements in the uncertainty budget for the measurement method.

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Dual radiofrequency drive quantum voltage standard with nanovolt resolution based on a closed-loop refrigeration cycle

Cited by 6 publications

References 18 publications

Quasi-continuous dc voltage standard using sinusoidal and pulse-driven Josephson junction arrays

Quasi-continuous dc voltage standard using sinusoidal and pulse-driven Josephson junction arrays

Maximizing the Resolution of a Dual RF Drive Programmable Josephson Voltage Standard

Automated direct comparison of two cryocooled 10 volt programmable Josephson voltage standards

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