Fig. 3: Characterization of mechanical mode and electromechanical coupling rate.
From: Large flux-mediated coupling in hybrid electromechanical system with a transmon qubit
a Color plot of the mixed-down signal VH as mechanical actuation frequency and dc voltage is varied. The mechanical resonance appears as a sharp change in the color. Blue(red) color represents low(high) values of the signal. To reduce the total measurement time, the mechanical actuation frequency range is automatically adjusted to follow the mechanical mode. b Average power spectral density (PSD) along with a fitted curve yielding a mechanical linewidth γm ~ 2π × 6 Hz corresponding to a quality factor of ~1.1 × 106. c Plot of the vacuum electromechanical coupling rate between hybridized mode and the mechanical resonator as the magnetic flux through the SQUID loop is increased, while ω+ = 2π × 6.025 GHz is kept fixed. The maximum flux applied corresponds to a field of 3.7 mT. The blue-dotted line shows the expected coupling rate calculated from the device parameters. The error bars represent the uncertainty resulting from the numerical fit of the PSD.
