Fig. 2: Dispersive sensing of the DQD at B = 0.
From: Strong coupling between a microwave photon and a singlet-triplet qubit
a Charge stability diagram of the device at B = 600 mT applied at α = 164° with respect to the NW, in which the resonator phase φ is measured as a function of the SG voltages VR and VL. A zoom on the interdot transition pointed out by the green rectangle is shown in b and c at B = 0 T and B = 300 mT with α = 57°, respectively. d Resonator transmission \({(A/{A}_{0})}^{2}\) versus probe frequency ωp and detuning ε (illustrated by the white line in b). At the charge degeneracy point of the DQD, we find a dispersive shift of 21 ± 2 MHz with respect to the bare resonance frequency. At small positive detuning a triplet state crosses the IDT, leading to a suppressed resonator transmission.
