All Pass Readout With Ring Resonators for Qubit Measurement

Abstract

Quantum computers may advance computing by solving some NP complexity problems, such as factoring and simulating quantum systems. Superconducting qubits, configurable artificial atoms comprised of circuit elements, are a leading platform to create quantum computers. Many schemes for superconducting qubit readout include a weakly coupled port as a capacitor in the feedline, which allows for directionality in the readout signal. However, this impedance mismatch creates problems with resonator linewidth variation, standing waves, and voltage nodes in the feedline, leading to challenges in scaling to larger frequency multiplexed systems. This thesis proposes an all-pass readout scheme that utilizes ring resonators that do not require a weakly coupled port, allowing for more modular qubit readout architectures.