研究実績の概要 |
To demonstrate a true random number generator (TRNG) based on quantum fluctuation,an novel Half-flux-quantum (HFQ) balanced comparater composed of π-π-π SQUIDs was proposed as TRNG. The nominal critical current of π-π-π SQUIDs can be reduced to 100 nA, which means the HFQ circuit can operate in the quantum regime at 10mK stage. In this study,the properties of SFIS (Nb/NiPd/Al-AlOx/Nb)π-JJs were characterized with temperature dependence. The intrinsic π phase shift can still be mentained at 10mK stage and the critical current density is only slightly increased than 4K, which is important for HFQ circuits. The correct operation of HFQ TFF was measured up to 6.7GHz and the un-shunted conventional single-flux-quantum (SFQ) circuits with SFQ/DC converts based on π-JJs were demonstrate at 4K.
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