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Kinetic Inductance Traveling Wave Amplifiers For Multiplexed Qubit Readout



Leonardo Ranzani, K. C. Fong, G. Ribell, Tomas A. Ohki, David P. Pappas, Mustafa Bal, Xian Wu, Robert P. Erickson, Junling Long, Hsiang S. Ku


We describe a kinetic inductance traveling-wave (KIT) amplifier suitable for superconducting quantum information measurements and characterize its wideband scattering and noise properties. We use mechanical microwave switches to calibrate the four amplifier scattering parameters up to the device input and output connectors at the dilution refrigerator base temperature and a tunable temperature load to characterize the amplifier noise. Finally, we demonstrate the high fidelity simultaneous dispersive readout of two superconducting transmon qubits. The KIT amplifier provides low-noise amplification of both readout tones with readout fidelities in excess of 89% and negligible effect on qubit lifetime and coherence.
Applied Physics Letters


Quantum information, amplifier, cryogenic, low noise, wide Bandwidth, high dynamic range
Created December 10, 2018, Updated December 14, 2018