Measuring the quality factor of a microwave cavity using superconducting qubit devices
Yu-xi Liu, L. F. Wei, Franco Nori · Physical Review A · 2005
We propose a method to create superpositions of two macroscopic quantum states of a single-mode microwave cavity field interacting with a superconducting charge qubit. The decoherence of such superpositions can be determined by measuring either the Wigner function of the cavity field or the charge qubit states. Then the quality factor $Q$ of the cavity can be inferred from the decoherence of the superposed states. The proposed method is experimentally realizable within current technology even when the $Q$ value is relatively low and the interaction between the qubit and the cavity field is weak.