Qubit energy tuner based on single flux quantum circuits

A device called qubit energy tuner (QET) based on single flux quantum (SFQ) circuits is proposed for Z control of superconducting qubits. Created from the improvement digital-to-analog converters (flux DACs), a QET able to set levels or frequencies qubits, especially flux-tunable transmons, and perform gate operations requiring control. The circuit structure elucidated, which consists an inductor loop bias units coarse tuning fine tuning. key feature analyzed understand how SFQ pulses change current, provides external To verify functionality QET, three simulations are carried out. first one verifies responses current pulses. results show that there about 4.2% relative deviation between analytical solutions WRSpice time-domain simulation. second third with QuTip iSWAP can be performed by this respectively, corresponding fidelities 99.99884% 99.93906% only once operation specific initial states. These indicate SFQ-based could act as efficient component quantum-classical interfaces digital large-scale computers.