Experimental Optimization of Kerr-Cat Qubit Readout

The Kerr-Cat qubit (KCQ) has attracted interest as ancilla for Quantum Error Correction (QEC) due to its noise-bias and long coherent state lifetimes. As with other types of qubits, fast and high-fidelity readout is an essential requirement for QEC with Kerr-Cat qubits. However, the parameter space of the Cat-Quadrature-Readout (CQR) of a KCQ is less well explored than that of common qubit types like the transmon. For example, the measurement rate of a KCQ depends on parameters like the size of the cat as well as the readout drive amplitude, both of which can be varied to increase fidelity and repeatability. Additionally, as the CQR displaces the readout cavity conditioned on the KCQ state, squeezing the input to the readout cavity could improve signal to noise ratio. Using an experimental setup with SNAIL Parametric Amplifiers on both the input and output of the KCQ, we will report on an experimental exploration of CQR, varying readout drive amplitude, cat size, and amplifier mode of operation.