Quantum Systems

Rapid single flux quantum (RSFQ) electronics is characterized by a very low switching energy. This advantage leads to a noise susceptibility which becomes a challenge for large-scale circuits as well as for circuits using Josephson junctions with reduced critical current density. We demonstrate an improved operation range and advanced noise immunity of basic cells resulting from an implemented phase shifting element. One of those elements is the pi-phaseshifter. It consists of a single flux quantum trapped in a superconducting loop. The pi-phaseshifter can be easily produced in standard Niobium technology without any process modifications. Utilizing a mature process brings advantages concerning the reliable fabrication of complex circuits.