The Quantum Architecture Group (QAG) develops materials, technologies, and prototypes for scalable quantum computation and microwave quantum optics with superconducting circuits. We are rapidly developing chips containing 10s of superconducting qubits by leveraging advances in material growth, nanofabrication, and the design of circuit QED systems. A key advance for the measurement of 10’s of superconducting qubits is a broadband amplifier called the Josephson traveling wave parametric amplifier (JTWPA), which has sufficient bandwidth and dynamic range to simultaneously read out 20 qubits.

Figure caption: Prototype multi-qubit chip. Five transmon qubits and readout resonators fabricated on-chip for simultaneous readout.

A recently developed travelling wave parametric amplifier (figure to the right) with a gain bandwidth orders of magnitude larger than existing amplifier technology while preserving their high quantum efficiency. The device consists of a over 2000 Josephson junctions and relies on a novel resonant metamaterial to allow for coherent buildup of the amplified signal across the device.

Figure caption: Josephson traveling wave parametric amplifier (JTWPA), a broadband low noise amplifier for superconducting qubit readout.