High coherence and low cross-talk in a superconducting qubit architecture

In a new report now published in Science Advances, Peter A. Spring and a team of scientists in physics at the Oxford University described qubit coherence and low cross-talk and single-qubit gate errors in superconducting qubit architecture, suited for two-dimensional (2D) lattices of qubits. The experimental setup involved an inductively shunted cavity enclosure with non-galvanic, out-of-plane control wiring, qubits and resonators fabricated on opposing sides of a substrate. The scientists developed a proof-of-concept device featuring four uncoupled transmon qubits, i.e., a superconducting charged qubit with reduced sensitivity to charge noise, to exhibit specific features measured via simultaneous randomized benchmarking. The three-dimensional integrated nature of the control wiring allowed the qubit to remain addressable as the architecture formed larger qubit lattices.