Multiphysics Numerical Methods for Designing Multiplexed Superconducting Qubit Readout Chains

Superconducting qubits require rapid and high-fidelity multiplexed readout to enable effective quantum computers. However, predicting the fidelity of the physical implementation of a readout chain is challenging, limiting the success of experimental devices. While analytical tools are currently used to support these design efforts, mapping their outputs into a physical design is difficult and prone to error. In this work, we use multiphysics numerical methods to model the effect of individual component values on fidelity, which can more easily guide the design of a physical device geometry. This procedure is utilized here to optimize a pair of key capacitance values, but it is applicable to broader parameterization of a readout chain.