Description of self-synchronization effects in distributed Josephson junction arrays using harmonic analysis and power balance

Power generation and synchronisation in Josephson junction arrays have attracted attention for a long time. This stems from fundamental interest in nonlinear coupled systems as well as from potential in practical applications. In this paper we study the case of an array of junctions coupled to a distributed transmission line either driven by an external microwave or in a self-oscillating mode. We simplify the theoretical treatment in terms of harmonic analysis and power balance. We apply the model to explain the large operation margins of SNS- and SINIS-junction arrays. We show the validity of the approach by comparing with experiments and simulations with self-oscillating es-SIS junction arrays.Comment: 5 pages, 3 figure

Progress Report on Closing the Quantum Metrological Triangle

Quantum Metrological Triangle is made out of three components: Josephson voltage standard, Quantum Hall resistance standard and an accurate current pump. Closing the Triangle consists of applying Ohm's law with great accuracy on the three devices, which are based on fundamental physical phenomena and quantities, such as Planck's constant and electron charge. The first two devices are already accepted international metrological standards. We will report on our recent progress in developing an accurate current pump, based on a hybrid single electron transistor, and compare it with other current pumps. We will also report on new ideas in developing the low noise current amplifier, needed for testing the Ohm's law, and describe our overall plans for closing the Triangle along with the expected uncertainties

Analysis of different measurement setups for a programmable Josephson voltage standard

The electrical characteristics of two different 1-V binary programmable Josephson arrays, an superconductor/insulator/normal conductor/insulator/superconductor-type Josephson array, and an externally shunted superconductor/insulator/superconductor-type Josephson array, were investigated at ten metrology institutes. Various operational parameters were evaluated and compared using different Josephson array voltage standard setups at microwave frequencies around 70 GHz. The results of the measurements show that both arrays have been working very well and the main differences were not imposed by the arrays themselves, but by the different measurement setups of the laboratories