Readout Induced Transitions in a Driven Superconducting Transmon Qubit*

Dispersive readout via a coupled resonator has become a staple component of high fidelity superconducting qubit systems. Ideally, reading out a qubit should not disturb its state, but previous work (Sank et al, PRL 117) has found that dispersive readout can cause undesired transitions in transmon qubits. In this talk, I will show that additional transitions are possible when the qubit is also driven, and that these transitions can be detected using qubit spectroscopy at high resonator photon numbers. These transitions can be predicted by examining the joint qubit-resonator states in the Jaynes-Cummings ladder. I will also show that this phenomenon has important consequences for readout in multiqubit devices.