Approaching Unit Visibility for Control of a Superconducting Qubit with Dispersive Readout
Andreas J. Wallraff, David Schuster, Alexandre Blais, Luigi Frunzio, Johannes Majer, Michel Devoret, S. M. Girvin, Robert J. Schoelkopf · Physical Review Letters · 2005
In a Rabi oscillation experiment with a superconducting qubit we show that a visibility in the qubit excited state population of more than 95% can be attained. We perform a dispersive measurement of the qubit state by coupling the qubit non-resonantly to a transmission line resonator and probing the resonator transmission spectrum. The measurement process is well characterized and quantitatively understood. In a measurement of Ramsey fringes, the qubit coherence time is larger than 500 ns.