Fig. 2

Ramsey interference for geometric phase. a Occupation probability P ₁ of Q₃ in \(\left| 1 \right\rangle\) as a function of θ and Ω ², which is measured using the pulse sequence shown in Fig. 1d with the drive detuning δ/2π = 4 MHz. b −β vs. Ω ² (red dots), where β is obtained by tracing the P ₁-maximum contour in a: For each Ramsey trace of P ₁ vs. θ sliced along a fixed Ω ², we perform the cosinusoidal fit with the phase offset giving the value of β. The blue solid line shows the theoretical result. c Measured average photon numbers with error bars of the resonator as functions of time during the application of the microwave drive with Ω/2π = 2 MHz conditional on the qubit states \(\left| 0 \right\rangle\) (blue dots) and \(\left| 1 \right\rangle\) (red dots). Error bars represent statistical errors (s.d.) of repeated sets of measurement. Lines are the numerical results