Experimental Realization of a Protected Superconducting Circuit Derived from the 0-pi Qubit

Encoding a qubit in logical quantum states with wave functions characterized by disjoint support and robust energies can offer simultaneous protection against relaxation and pure dephasing. One of the most promising candidates for a fully protected superconducting qubit is the 0–π . This article reports the first realization of this new qubit in an experimentally obtainable parameter regime, where the ground-state degeneracy is lifted but the qubit is still largely noise protected.