Study on the Quantum Current-Mirror Effect

点击翻译按钮获取中文摘要

The effect studied in this research is a precise electric current duplication between in two arrays of small Josephson junctions. The basis of this effect is the so called single-charge tunneling phenomenon. Therefore, correlation of Cooper-pair tunneling in the two arrays is expected in this phenomenon. In the period of this research, we have made the following achievements.1.We have succeeded in making a current doubler based on the current-mirror effect. Characteristics of the doubler device have been clarified from a practical point of view, such as circuit connection scheme, bias voltage range and its relation to the accuracy of the device. This realization of a current doubler is one of the main targets of this research.2.Several features of this effect has been clarified such as the relation between the Josephson coupling energy of each junction to the maximum duplicable current, the relation of the number of the junctions in the array which composes the current-mirror device with the mirror effect, bias voltage range for the mirror effect, etc.3.In a three-array device, we have observed a duplication of the current between arrays which are not directly connected through coupling capacitances. This is a remarkable phenomenon which has not been expected. And this implies that the effect is due to a nonlocal correlation of the Cooper-pair tunnelings in the different arrays rather than a local correlation of them.The final point brings a new interest on this effect and it will require more profound insight on the physics of small Josephson junction. So more works from new viewpoints are needed to understand this effect sufficiently.