Dispersive Qubit Readout (2D) — Circuit QED Measurement

This 2D companion to the 3D circuit-QED readout simulator strips the scene down to the part that actually carries the information: a pannable, zoomable IQ plane driven by the exact same dispersive-shift model. A transmon qubit's state pulls its readout resonator's frequency by ±χ, so driving that resonator produces two distinct coherent pointer states that separate on the plane. Tuning the qubit-resonator coupling g, the drive amplitude ε and the integration time τ reshapes the pointer separation and the noise floor live, while firing batches of single-shot measurements shows the discrimination fidelity a real readout chain would achieve. Drag to pan and scroll to zoom in on the pointer-state clouds; the qubit and resonator badges in the corner track the same live state.