Predicting the Fidelity of Multiplexed Superconducting Qubit Readout with Multiphysics Numerical Methods

Josephson traveling-wave parametric amplifiers are a critical component for enabling multiplexed qubit readout. However, these devices introduce nonideal effects which make optimizing the readout circuitry highly challenging. Here, we introduce an approach to model a readout chain which incorporates these effects to calculate readout fidelity, and demonstrate how it can be used to evaluate trade-offs between competing factors in a readout chain design.