Readout fidelity of Floquet optimized low anharmonicity transmons

High-fidelity, quantum non-demolition readout is important for state-of-the-art operation of quantum computers. Performing strong, projective measurements on a transmon qubit causes spurious transitions due to high-order parametric processes, causing the qubit to change states and disrupting the QND-ness of the dispersive readout. Utilizing Floquet simulations to model the qubit subject to these strong drives is useful to determine which qubit and readout cavity choices are limited by these transitions. In this talk, we explore how the landscape of these multi-photon processes change by reducing the anharmonicity of the transmon qubit. We show that for such transmons, the frequency gaps between transitions are substantially wider for readout frequencies above the qubit as compared to higher-anharmonicity qubits with nominally identical frequencies, allowing for stronger drives and faster readout.